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CHANGELOG.md
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## ClickHouse release 20.11
### ClickHouse release v20.11.3.3-stable, 2020-11-13
#### Bug Fix
* Fix rare silent crashes when query profiler is on and ClickHouse is installed on OS with glibc version that has (supposedly) broken asynchronous unwind tables for some functions. This fixes [#15301](https://github.com/ClickHouse/ClickHouse/issues/15301). This fixes [#13098](https://github.com/ClickHouse/ClickHouse/issues/13098). [#16846](https://github.com/ClickHouse/ClickHouse/pull/16846) ([alexey-milovidov](https://github.com/alexey-milovidov)).
### ClickHouse release v20.11.2.1, 2020-11-11
#### Backward Incompatible Change
* If some `profile` was specified in `distributed_ddl` config section, then this profile could overwrite settings of `default` profile on server startup. It's fixed, now settings of distributed DDL queries should not affect global server settings. [#16635](https://github.com/ClickHouse/ClickHouse/pull/16635) ([tavplubix](https://github.com/tavplubix)).
* Restrict to use of non-comparable data types (like `AggregateFunction`) in keys (Sorting key, Primary key, Partition key, and so on). [#16601](https://github.com/ClickHouse/ClickHouse/pull/16601) ([alesapin](https://github.com/alesapin)).
* Remove `ANALYZE` and `AST` queries, and make the setting `enable_debug_queries` obsolete since now it is the part of full featured `EXPLAIN` query. [#16536](https://github.com/ClickHouse/ClickHouse/pull/16536) ([Ivan](https://github.com/abyss7)).
* Aggregate functions `boundingRatio`, `rankCorr`, `retention`, `timeSeriesGroupSum`, `timeSeriesGroupRateSum`, `windowFunnel` were erroneously made case-insensitive. Now their names are made case sensitive as designed. Only functions that are specified in SQL standard or made for compatibility with other DBMS or functions similar to those should be case-insensitive. [#16407](https://github.com/ClickHouse/ClickHouse/pull/16407) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Make `rankCorr` function return nan on insufficient data https://github.com/ClickHouse/ClickHouse/issues/16124. [#16135](https://github.com/ClickHouse/ClickHouse/pull/16135) ([hexiaoting](https://github.com/hexiaoting)).
#### New Feature
* Added support of LDAP as a user directory for locally non-existent users. [#12736](https://github.com/ClickHouse/ClickHouse/pull/12736) ([Denis Glazachev](https://github.com/traceon)).
* Add `system.replicated_fetches` table which shows currently running background fetches. [#16428](https://github.com/ClickHouse/ClickHouse/pull/16428) ([alesapin](https://github.com/alesapin)).
* Added setting `date_time_output_format`. [#15845](https://github.com/ClickHouse/ClickHouse/pull/15845) ([Maksim Kita](https://github.com/kitaisreal)).
* Added minimal web UI to ClickHouse. [#16158](https://github.com/ClickHouse/ClickHouse/pull/16158) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Allows to read/write Single protobuf message at once (w/o length-delimiters). [#15199](https://github.com/ClickHouse/ClickHouse/pull/15199) ([filimonov](https://github.com/filimonov)).
* Added initial OpenTelemetry support. ClickHouse now accepts OpenTelemetry traceparent headers over Native and HTTP protocols, and passes them downstream in some cases. The trace spans for executed queries are saved into the `system.opentelemetry_span_log` table. [#14195](https://github.com/ClickHouse/ClickHouse/pull/14195) ([Alexander Kuzmenkov](https://github.com/akuzm)).
* Allow specify primary key in column list of `CREATE TABLE` query. This is needed for compatibility with other SQL dialects. [#15823](https://github.com/ClickHouse/ClickHouse/pull/15823) ([Maksim Kita](https://github.com/kitaisreal)).
* Implement `OFFSET offset_row_count {ROW | ROWS} FETCH {FIRST | NEXT} fetch_row_count {ROW | ROWS} {ONLY | WITH TIES}` in SELECT query with ORDER BY. This is the SQL-standard way to specify `LIMIT`. [#15855](https://github.com/ClickHouse/ClickHouse/pull/15855) ([hexiaoting](https://github.com/hexiaoting)).
* `errorCodeToName` function - return variable name of the error (useful for analyzing query_log and similar). `system.errors` table - shows how many times errors has been happened (respects `system_events_show_zero_values`). [#16438](https://github.com/ClickHouse/ClickHouse/pull/16438) ([Azat Khuzhin](https://github.com/azat)).
* Added function `untuple` which is a special function which can introduce new columns to the SELECT list by expanding a named tuple. [#16242](https://github.com/ClickHouse/ClickHouse/pull/16242) ([Nikolai Kochetov](https://github.com/KochetovNicolai), [Amos Bird](https://github.com/amosbird)).
* Now we can provide identifiers via query parameters. And these parameters can be used as table objects or columns. [#16594](https://github.com/ClickHouse/ClickHouse/pull/16594) ([Amos Bird](https://github.com/amosbird)).
* Added big integers (UInt256, Int128, Int256) and UUID data types support for MergeTree BloomFilter index. Big integers is an experimental feature. [#16642](https://github.com/ClickHouse/ClickHouse/pull/16642) ([Maksim Kita](https://github.com/kitaisreal)).
* Add `farmFingerprint64` function (non-cryptographic string hashing). [#16570](https://github.com/ClickHouse/ClickHouse/pull/16570) ([Jacob Hayes](https://github.com/JacobHayes)).
* Add `log_queries_min_query_duration_ms`, only queries slower then the value of this setting will go to `query_log`/`query_thread_log` (i.e. something like `slow_query_log` in mysql). [#16529](https://github.com/ClickHouse/ClickHouse/pull/16529) ([Azat Khuzhin](https://github.com/azat)).
* Ability to create a docker image on the top of `Alpine`. Uses precompiled binary and glibc components from ubuntu 20.04. [#16479](https://github.com/ClickHouse/ClickHouse/pull/16479) ([filimonov](https://github.com/filimonov)).
* Added `toUUIDOrNull`, `toUUIDOrZero` cast functions. [#16337](https://github.com/ClickHouse/ClickHouse/pull/16337) ([Maksim Kita](https://github.com/kitaisreal)).
* Add `max_concurrent_queries_for_all_users` setting, see [#6636](https://github.com/ClickHouse/ClickHouse/issues/6636) for use cases. [#16154](https://github.com/ClickHouse/ClickHouse/pull/16154) ([nvartolomei](https://github.com/nvartolomei)).
* Add a new option `print_query_id` to clickhouse-client. It helps generate arbitrary strings with the current query id generated by the client. Also print query id in clickhouse-client by default. [#15809](https://github.com/ClickHouse/ClickHouse/pull/15809) ([Amos Bird](https://github.com/amosbird)).
* Add `tid` and `logTrace` functions. This closes [#9434](https://github.com/ClickHouse/ClickHouse/issues/9434). [#15803](https://github.com/ClickHouse/ClickHouse/pull/15803) ([flynn](https://github.com/ucasFL)).
* Add function `formatReadableTimeDelta` that format time delta to human readable string ... [#15497](https://github.com/ClickHouse/ClickHouse/pull/15497) ([Filipe Caixeta](https://github.com/filipecaixeta)).
* Added `disable_merges` option for volumes in multi-disk configuration. [#13956](https://github.com/ClickHouse/ClickHouse/pull/13956) ([Vladimir Chebotarev](https://github.com/excitoon)).
#### Experimental Feature
* New functions `encrypt`, `aes_encrypt_mysql`, `decrypt`, `aes_decrypt_mysql`. These functions are working slowly, so we consider it as an experimental feature. [#11844](https://github.com/ClickHouse/ClickHouse/pull/11844) ([Vasily Nemkov](https://github.com/Enmk)).
#### Bug Fix
* Mask password in data_path in the `system.distribution_queue`. [#16727](https://github.com/ClickHouse/ClickHouse/pull/16727) ([Azat Khuzhin](https://github.com/azat)).
* Fix `IN` operator over several columns and tuples with enabled `transform_null_in` setting. Fixes [#15310](https://github.com/ClickHouse/ClickHouse/issues/15310). [#16722](https://github.com/ClickHouse/ClickHouse/pull/16722) ([Anton Popov](https://github.com/CurtizJ)).
* The setting `max_parallel_replicas` worked incorrectly if the queried table has no sampling. This fixes [#5733](https://github.com/ClickHouse/ClickHouse/issues/5733). [#16675](https://github.com/ClickHouse/ClickHouse/pull/16675) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix optimize_read_in_order/optimize_aggregation_in_order with max_threads > 0 and expression in ORDER BY. [#16637](https://github.com/ClickHouse/ClickHouse/pull/16637) ([Azat Khuzhin](https://github.com/azat)).
* Calculation of `DEFAULT` expressions was involving possible name collisions (that was very unlikely to encounter). This fixes [#9359](https://github.com/ClickHouse/ClickHouse/issues/9359). [#16612](https://github.com/ClickHouse/ClickHouse/pull/16612) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix `query_thread_log.query_duration_ms` unit. [#16563](https://github.com/ClickHouse/ClickHouse/pull/16563) ([Azat Khuzhin](https://github.com/azat)).
* Fix a bug when using MySQL Master -> MySQL Slave -> ClickHouse MaterializeMySQL Engine. `MaterializeMySQL` is an experimental feature. [#16504](https://github.com/ClickHouse/ClickHouse/pull/16504) ([TCeason](https://github.com/TCeason)).
* Specifically crafted argument of `round` function with `Decimal` was leading to integer division by zero. This fixes [#13338](https://github.com/ClickHouse/ClickHouse/issues/13338). [#16451](https://github.com/ClickHouse/ClickHouse/pull/16451) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix DROP TABLE for Distributed (racy with INSERT). [#16409](https://github.com/ClickHouse/ClickHouse/pull/16409) ([Azat Khuzhin](https://github.com/azat)).
* Fix processing of very large entries in replication queue. Very large entries may appear in ALTER queries if table structure is extremely large (near 1 MB). This fixes [#16307](https://github.com/ClickHouse/ClickHouse/issues/16307). [#16332](https://github.com/ClickHouse/ClickHouse/pull/16332) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fixed the inconsistent behaviour when a part of return data could be dropped because the set for its filtration wasn't created. [#16308](https://github.com/ClickHouse/ClickHouse/pull/16308) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Fix dictGet in sharding_key (and similar places, i.e. when the function context is stored permanently). [#16205](https://github.com/ClickHouse/ClickHouse/pull/16205) ([Azat Khuzhin](https://github.com/azat)).
* Fix the exception thrown in `clickhouse-local` when trying to execute `OPTIMIZE` command. Fixes [#16076](https://github.com/ClickHouse/ClickHouse/issues/16076). [#16192](https://github.com/ClickHouse/ClickHouse/pull/16192) ([filimonov](https://github.com/filimonov)).
* Fixes [#15780](https://github.com/ClickHouse/ClickHouse/issues/15780) regression, e.g. `indexOf([1, 2, 3], toLowCardinality(1))` now is prohibited but it should not be. [#16038](https://github.com/ClickHouse/ClickHouse/pull/16038) ([Mike](https://github.com/myrrc)).
* Fix bug with MySQL database. When MySQL server used as database engine is down some queries raise Exception, because they try to get tables from disabled server, while it's unnecessary. For example, query `SELECT ... FROM system.parts` should work only with MergeTree tables and don't touch MySQL database at all. [#16032](https://github.com/ClickHouse/ClickHouse/pull/16032) ([Kruglov Pavel](https://github.com/Avogar)).
* Now exception will be thrown when `ALTER MODIFY COLUMN ... DEFAULT ...` has incompatible default with column type. Fixes [#15854](https://github.com/ClickHouse/ClickHouse/issues/15854). [#15858](https://github.com/ClickHouse/ClickHouse/pull/15858) ([alesapin](https://github.com/alesapin)).
* Fixed IPv4CIDRToRange/IPv6CIDRToRange functions to accept const IP-column values. [#15856](https://github.com/ClickHouse/ClickHouse/pull/15856) ([vladimir-golovchenko](https://github.com/vladimir-golovchenko)).
#### Improvement
* Treat `INTERVAL '1 hour'` as equivalent to `INTERVAL 1 HOUR`, to be compatible with Postgres and similar. This fixes [#15637](https://github.com/ClickHouse/ClickHouse/issues/15637). [#15978](https://github.com/ClickHouse/ClickHouse/pull/15978) ([flynn](https://github.com/ucasFL)).
* Enable parsing enum values by their numeric ids for CSV, TSV and JSON input formats. [#15685](https://github.com/ClickHouse/ClickHouse/pull/15685) ([vivarum](https://github.com/vivarum)).
* Better read task scheduling for JBOD architecture and `MergeTree` storage. New setting `read_backoff_min_concurrency` which serves as the lower limit to the number of reading threads. [#16423](https://github.com/ClickHouse/ClickHouse/pull/16423) ([Amos Bird](https://github.com/amosbird)).
* Add missing support for `LowCardinality` in `Avro` format. [#16521](https://github.com/ClickHouse/ClickHouse/pull/16521) ([Mike](https://github.com/myrrc)).
* Workaround for use `S3` with nginx server as proxy. Nginx currenty does not accept urls with empty path like `http://domain.com?delete`, but vanilla aws-sdk-cpp produces this kind of urls. This commit uses patched aws-sdk-cpp version, which makes urls with "/" as path in this cases, like `http://domain.com/?delete`. [#16814](https://github.com/ClickHouse/ClickHouse/pull/16814) ([ianton-ru](https://github.com/ianton-ru)).
* Better diagnostics on parse errors in input data. Provide row number on `Cannot read all data` errors. [#16644](https://github.com/ClickHouse/ClickHouse/pull/16644) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Make the behaviour of `minMap` and `maxMap` more desireable. It will not skip zero values in the result. Fixes [#16087](https://github.com/ClickHouse/ClickHouse/issues/16087). [#16631](https://github.com/ClickHouse/ClickHouse/pull/16631) ([Ildus Kurbangaliev](https://github.com/ildus)).
* Better update of ZooKeeper configuration in runtime. [#16630](https://github.com/ClickHouse/ClickHouse/pull/16630) ([sundyli](https://github.com/sundy-li)).
* Apply SETTINGS clause as early as possible. It allows to modify more settings in the query. This closes [#3178](https://github.com/ClickHouse/ClickHouse/issues/3178). [#16619](https://github.com/ClickHouse/ClickHouse/pull/16619) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Now `event_time_microseconds` field stores in Decimal64, not UInt64. [#16617](https://github.com/ClickHouse/ClickHouse/pull/16617) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Now paratmeterized functions can be used in `APPLY` column transformer. [#16589](https://github.com/ClickHouse/ClickHouse/pull/16589) ([Amos Bird](https://github.com/amosbird)).
* Improve scheduling of background task which removes data of dropped tables in `Atomic` databases. `Atomic` databases do not create broken symlink to table data directory if table actually has no data directory. [#16584](https://github.com/ClickHouse/ClickHouse/pull/16584) ([tavplubix](https://github.com/tavplubix)).
* Subqueries in `WITH` section (CTE) can reference previous subqueries in `WITH` section by their name. [#16575](https://github.com/ClickHouse/ClickHouse/pull/16575) ([Amos Bird](https://github.com/amosbird)).
* Add current_database into `system.query_thread_log`. [#16558](https://github.com/ClickHouse/ClickHouse/pull/16558) ([Azat Khuzhin](https://github.com/azat)).
* Allow to fetch parts that are already committed or outdated in the current instance into the detached directory. It's useful when migrating tables from another cluster and having N to 1 shards mapping. It's also consistent with the current fetchPartition implementation. [#16538](https://github.com/ClickHouse/ClickHouse/pull/16538) ([Amos Bird](https://github.com/amosbird)).
* Multiple improvements for `RabbitMQ`: Fixed bug for [#16263](https://github.com/ClickHouse/ClickHouse/issues/16263). Also minimized event loop lifetime. Added more efficient queues setup. [#16426](https://github.com/ClickHouse/ClickHouse/pull/16426) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix debug assertion in `quantileDeterministic` function. In previous version it may also transfer up to two times more data over the network. Although no bug existed. This fixes [#15683](https://github.com/ClickHouse/ClickHouse/issues/15683). [#16410](https://github.com/ClickHouse/ClickHouse/pull/16410) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add `TablesToDropQueueSize` metric. It's equal to number of dropped tables, that are waiting for background data removal. [#16364](https://github.com/ClickHouse/ClickHouse/pull/16364) ([tavplubix](https://github.com/tavplubix)).
* Better diagnostics when client has dropped connection. In previous versions, `Attempt to read after EOF` and `Broken pipe` exceptions were logged in server. In new version, it's information message `Client has dropped the connection, cancel the query.`. [#16329](https://github.com/ClickHouse/ClickHouse/pull/16329) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add total_rows/total_bytes (from system.tables) support for Set/Join table engines. [#16306](https://github.com/ClickHouse/ClickHouse/pull/16306) ([Azat Khuzhin](https://github.com/azat)).
* Now it's possible to specify `PRIMARY KEY` without `ORDER BY` for MergeTree table engines family. Closes [#15591](https://github.com/ClickHouse/ClickHouse/issues/15591). [#16284](https://github.com/ClickHouse/ClickHouse/pull/16284) ([alesapin](https://github.com/alesapin)).
* If there is no tmp folder in the system (chroot, misconfigutation etc) `clickhouse-local` will create temporary subfolder in the current directory. [#16280](https://github.com/ClickHouse/ClickHouse/pull/16280) ([filimonov](https://github.com/filimonov)).
* Add support for nested data types (like named tuple) as sub-types. Fixes [#15587](https://github.com/ClickHouse/ClickHouse/issues/15587). [#16262](https://github.com/ClickHouse/ClickHouse/pull/16262) ([Ivan](https://github.com/abyss7)).
* Support for `database_atomic_wait_for_drop_and_detach_synchronously`/`NO DELAY`/`SYNC` for `DROP DATABASE`. [#16127](https://github.com/ClickHouse/ClickHouse/pull/16127) ([Azat Khuzhin](https://github.com/azat)).
* Add `allow_nondeterministic_optimize_skip_unused_shards` (to allow non deterministic like `rand()` or `dictGet()` in sharding key). [#16105](https://github.com/ClickHouse/ClickHouse/pull/16105) ([Azat Khuzhin](https://github.com/azat)).
* Fix `memory_profiler_step`/`max_untracked_memory` for queries via HTTP (test included). Fix the issue that adjusting this value globally in xml config does not help either, since those settings are not applied anyway, only default (4MB) value is [used](https://github.com/ClickHouse/ClickHouse/blob/17731245336d8c84f75e4c0894c5797ed7732190/src/Common/ThreadStatus.h#L104). Fix `query_id` for the most root ThreadStatus of the http query (by initializing QueryScope after reading query_id). [#16101](https://github.com/ClickHouse/ClickHouse/pull/16101) ([Azat Khuzhin](https://github.com/azat)).
* Now it's allowed to execute `ALTER ... ON CLUSTER` queries regardless of the `<internal_replication>` setting in cluster config. [#16075](https://github.com/ClickHouse/ClickHouse/pull/16075) ([alesapin](https://github.com/alesapin)).
* Fix rare issue when `clickhouse-client` may abort on exit due to loading of suggestions. This fixes [#16035](https://github.com/ClickHouse/ClickHouse/issues/16035). [#16047](https://github.com/ClickHouse/ClickHouse/pull/16047) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add support of `cache` layout for `Redis` dictionaries with complex key. [#15985](https://github.com/ClickHouse/ClickHouse/pull/15985) ([Anton Popov](https://github.com/CurtizJ)).
* Fix query hang (endless loop) in case of misconfiguration (`connections_with_failover_max_tries` set to 0). [#15876](https://github.com/ClickHouse/ClickHouse/pull/15876) ([Azat Khuzhin](https://github.com/azat)).
* Change level of some log messages from information to debug, so information messages will not appear for every query. This closes [#5293](https://github.com/ClickHouse/ClickHouse/issues/5293). [#15816](https://github.com/ClickHouse/ClickHouse/pull/15816) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Remove `MemoryTrackingInBackground*` metrics to avoid potentially misleading results. This fixes [#15684](https://github.com/ClickHouse/ClickHouse/issues/15684). [#15813](https://github.com/ClickHouse/ClickHouse/pull/15813) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add reconnects to `zookeeper-dump-tree` tool. [#15711](https://github.com/ClickHouse/ClickHouse/pull/15711) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Allow explicitly specify columns list in `CREATE TABLE table AS table_function(...)` query. Fixes [#9249](https://github.com/ClickHouse/ClickHouse/issues/9249) Fixes [#14214](https://github.com/ClickHouse/ClickHouse/issues/14214). [#14295](https://github.com/ClickHouse/ClickHouse/pull/14295) ([tavplubix](https://github.com/tavplubix)).
#### Performance Improvement
* Do not merge parts across partitions in SELECT FINAL. [#15938](https://github.com/ClickHouse/ClickHouse/pull/15938) ([Kruglov Pavel](https://github.com/Avogar)).
* Improve performance of `-OrNull` and `-OrDefault` aggregate functions. [#16661](https://github.com/ClickHouse/ClickHouse/pull/16661) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Improve performance of `quantileMerge`. In previous versions it was obnoxiously slow. This closes [#1463](https://github.com/ClickHouse/ClickHouse/issues/1463). [#16643](https://github.com/ClickHouse/ClickHouse/pull/16643) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Improve performance of logical functions a little. [#16347](https://github.com/ClickHouse/ClickHouse/pull/16347) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Improved performance of merges assignment in MergeTree table engines. Shouldn't be visible for the user. [#16191](https://github.com/ClickHouse/ClickHouse/pull/16191) ([alesapin](https://github.com/alesapin)).
* Speedup hashed/sparse_hashed dictionary loading by preallocating the hash table. [#15454](https://github.com/ClickHouse/ClickHouse/pull/15454) ([Azat Khuzhin](https://github.com/azat)).
* Now trivial count optimization becomes slightly non-trivial. Predicates that contain exact partition expr can be optimized too. This also fixes [#11092](https://github.com/ClickHouse/ClickHouse/issues/11092) which returns wrong count when `max_parallel_replicas > 1`. [#15074](https://github.com/ClickHouse/ClickHouse/pull/15074) ([Amos Bird](https://github.com/amosbird)).
#### Build/Testing/Packaging Improvement
* Add flaky check for stateless tests. It will detect potentially flaky functional tests in advance, before they are merged. [#16238](https://github.com/ClickHouse/ClickHouse/pull/16238) ([alesapin](https://github.com/alesapin)).
* Use proper version for `croaring` instead of amalgamation. [#16285](https://github.com/ClickHouse/ClickHouse/pull/16285) ([sundyli](https://github.com/sundy-li)).
* Improve generation of build files for `ya.make` build system (Arcadia). [#16700](https://github.com/ClickHouse/ClickHouse/pull/16700) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add MySQL BinLog file check tool for `MaterializeMySQL` database engine. `MaterializeMySQL` is an experimental feature. [#16223](https://github.com/ClickHouse/ClickHouse/pull/16223) ([Winter Zhang](https://github.com/zhang2014)).
* Check for executable bit on non-executable files. People often accidentially commit executable files from Windows. [#15843](https://github.com/ClickHouse/ClickHouse/pull/15843) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Check for `#pragma once` in headers. [#15818](https://github.com/ClickHouse/ClickHouse/pull/15818) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix illegal code style `&vector[idx]` in libhdfs3. This fixes libcxx debug build. See also https://github.com/ClickHouse-Extras/libhdfs3/pull/8 . [#15815](https://github.com/ClickHouse/ClickHouse/pull/15815) ([Amos Bird](https://github.com/amosbird)).
* Fix build of one miscellaneous example tool on Mac OS. Note that we don't build examples on Mac OS in our CI (we build only ClickHouse binary), so there is zero chance it will not break again. This fixes [#15804](https://github.com/ClickHouse/ClickHouse/issues/15804). [#15808](https://github.com/ClickHouse/ClickHouse/pull/15808) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Simplify Sys/V init script. [#14135](https://github.com/ClickHouse/ClickHouse/pull/14135) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Added `boost::program_options` to `db_generator` in order to increase its usability. This closes [#15940](https://github.com/ClickHouse/ClickHouse/issues/15940). [#15973](https://github.com/ClickHouse/ClickHouse/pull/15973) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
## ClickHouse release 20.10
### ClickHouse release v20.10.4.1-stable, 2020-11-13
#### Bug Fix
* Fix rare silent crashes when query profiler is on and ClickHouse is installed on OS with glibc version that has (supposedly) broken asynchronous unwind tables for some functions. This fixes [#15301](https://github.com/ClickHouse/ClickHouse/issues/15301). This fixes [#13098](https://github.com/ClickHouse/ClickHouse/issues/13098). [#16846](https://github.com/ClickHouse/ClickHouse/pull/16846) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix `IN` operator over several columns and tuples with enabled `transform_null_in` setting. Fixes [#15310](https://github.com/ClickHouse/ClickHouse/issues/15310). [#16722](https://github.com/ClickHouse/ClickHouse/pull/16722) ([Anton Popov](https://github.com/CurtizJ)).
* This will fix optimize_read_in_order/optimize_aggregation_in_order with max_threads>0 and expression in ORDER BY. [#16637](https://github.com/ClickHouse/ClickHouse/pull/16637) ([Azat Khuzhin](https://github.com/azat)).
* Now when parsing AVRO from input the LowCardinality is removed from type. Fixes [#16188](https://github.com/ClickHouse/ClickHouse/issues/16188). [#16521](https://github.com/ClickHouse/ClickHouse/pull/16521) ([Mike](https://github.com/myrrc)).
* Fix rapid growth of metadata when using MySQL Master -> MySQL Slave -> ClickHouse MaterializeMySQL Engine, and `slave_parallel_worker` enabled on MySQL Slave, by properly shrinking GTID sets. This fixes [#15951](https://github.com/ClickHouse/ClickHouse/issues/15951). [#16504](https://github.com/ClickHouse/ClickHouse/pull/16504) ([TCeason](https://github.com/TCeason)).
* Fix DROP TABLE for Distributed (racy with INSERT). [#16409](https://github.com/ClickHouse/ClickHouse/pull/16409) ([Azat Khuzhin](https://github.com/azat)).
* Fix processing of very large entries in replication queue. Very large entries may appear in ALTER queries if table structure is extremely large (near 1 MB). This fixes [#16307](https://github.com/ClickHouse/ClickHouse/issues/16307). [#16332](https://github.com/ClickHouse/ClickHouse/pull/16332) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix bug with MySQL database. When MySQL server used as database engine is down some queries raise Exception, because they try to get tables from disabled server, while it's unnecessary. For example, query `SELECT ... FROM system.parts` should work only with MergeTree tables and don't touch MySQL database at all. [#16032](https://github.com/ClickHouse/ClickHouse/pull/16032) ([Kruglov Pavel](https://github.com/Avogar)).
#### Improvement
* Workaround for use S3 with nginx server as proxy. Nginx currenty does not accept urls with empty path like http://domain.com?delete, but vanilla aws-sdk-cpp produces this kind of urls. This commit uses patched aws-sdk-cpp version, which makes urls with "/" as path in this cases, like http://domain.com/?delete. [#16813](https://github.com/ClickHouse/ClickHouse/pull/16813) ([ianton-ru](https://github.com/ianton-ru)).
### ClickHouse release v20.10.3.30, 2020-10-28
#### Backward Incompatible Change
* Make `multiple_joins_rewriter_version` obsolete. Remove first version of joins rewriter. [#15472](https://github.com/ClickHouse/ClickHouse/pull/15472) ([Artem Zuikov](https://github.com/4ertus2)).
* Change default value of `format_regexp_escaping_rule` setting (it's related to `Regexp` format) to `Raw` (it means - read whole subpattern as a value) to make the behaviour more like to what users expect. [#15426](https://github.com/ClickHouse/ClickHouse/pull/15426) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add support for nested multiline comments `/* comment /* comment */ */` in SQL. This conforms to the SQL standard. [#14655](https://github.com/ClickHouse/ClickHouse/pull/14655) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Added MergeTree settings (`max_replicated_merges_with_ttl_in_queue` and `max_number_of_merges_with_ttl_in_pool`) to control the number of merges with TTL in the background pool and replicated queue. This change breaks compatibility with older versions only if you use delete TTL. Otherwise, replication will stay compatible. You can avoid incompatibility issues if you update all shard replicas at once or execute `SYSTEM STOP TTL MERGES` until you finish the update of all replicas. If you'll get an incompatible entry in the replication queue, first of all, execute `SYSTEM STOP TTL MERGES` and after `ALTER TABLE ... DETACH PARTITION ...` the partition where incompatible TTL merge was assigned. Attach it back on a single replica. [#14490](https://github.com/ClickHouse/ClickHouse/pull/14490) ([alesapin](https://github.com/alesapin)).
#### New Feature
* Background data recompression. Add the ability to specify `TTL ... RECOMPRESS codec_name` for MergeTree table engines family. [#14494](https://github.com/ClickHouse/ClickHouse/pull/14494) ([alesapin](https://github.com/alesapin)).
* Add parallel quorum inserts. This closes [#15601](https://github.com/ClickHouse/ClickHouse/issues/15601). [#15601](https://github.com/ClickHouse/ClickHouse/pull/15601) ([Latysheva Alexandra](https://github.com/alexelex)).
* Settings for additional enforcement of data durability. Useful for non-replicated setups. [#11948](https://github.com/ClickHouse/ClickHouse/pull/11948) ([Anton Popov](https://github.com/CurtizJ)).
* When duplicate block is written to replica where it does not exist locally (has not been fetched from replicas), don't ignore it and write locally to achieve the same effect as if it was successfully replicated. [#11684](https://github.com/ClickHouse/ClickHouse/pull/11684) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Now we support `WITH <identifier> AS (subquery) ... ` to introduce named subqueries in the query context. This closes [#2416](https://github.com/ClickHouse/ClickHouse/issues/2416). This closes [#4967](https://github.com/ClickHouse/ClickHouse/issues/4967). [#14771](https://github.com/ClickHouse/ClickHouse/pull/14771) ([Amos Bird](https://github.com/amosbird)).
* Introduce `enable_global_with_statement` setting which propagates the first select's `WITH` statements to other select queries at the same level, and makes aliases in `WITH` statements visible to subqueries. [#15451](https://github.com/ClickHouse/ClickHouse/pull/15451) ([Amos Bird](https://github.com/amosbird)).
* Secure inter-cluster query execution (with initial_user as current query user). [#13156](https://github.com/ClickHouse/ClickHouse/pull/13156) ([Azat Khuzhin](https://github.com/azat)). [#15551](https://github.com/ClickHouse/ClickHouse/pull/15551) ([Azat Khuzhin](https://github.com/azat)).
* Add the ability to remove column properties and table TTLs. Introduced queries `ALTER TABLE MODIFY COLUMN col_name REMOVE what_to_remove` and `ALTER TABLE REMOVE TTL`. Both operations are lightweight and executed at the metadata level. [#14742](https://github.com/ClickHouse/ClickHouse/pull/14742) ([alesapin](https://github.com/alesapin)).
* Added format `RawBLOB`. It is intended for input or output a single value without any escaping and delimiters. This closes [#15349](https://github.com/ClickHouse/ClickHouse/issues/15349). [#15364](https://github.com/ClickHouse/ClickHouse/pull/15364) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add the `reinterpretAsUUID` function that allows to convert a big-endian byte string to UUID. [#15480](https://github.com/ClickHouse/ClickHouse/pull/15480) ([Alexander Kuzmenkov](https://github.com/akuzm)).
* Implement `force_data_skipping_indices` setting. [#15642](https://github.com/ClickHouse/ClickHouse/pull/15642) ([Azat Khuzhin](https://github.com/azat)).
* Add a setting `output_format_pretty_row_numbers` to numerate the result in Pretty formats. This closes [#15350](https://github.com/ClickHouse/ClickHouse/issues/15350). [#15443](https://github.com/ClickHouse/ClickHouse/pull/15443) ([flynn](https://github.com/ucasFL)).
* Added query obfuscation tool. It allows to share more queries for better testing. This closes [#15268](https://github.com/ClickHouse/ClickHouse/issues/15268). [#15321](https://github.com/ClickHouse/ClickHouse/pull/15321) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add table function `null('structure')`. [#14797](https://github.com/ClickHouse/ClickHouse/pull/14797) ([vxider](https://github.com/Vxider)).
* Added `formatReadableQuantity` function. It is useful for reading big numbers by human. [#14725](https://github.com/ClickHouse/ClickHouse/pull/14725) ([Artem Hnilov](https://github.com/BooBSD)).
* Add format `LineAsString` that accepts a sequence of lines separated by newlines, every line is parsed as a whole as a single String field. [#14703](https://github.com/ClickHouse/ClickHouse/pull/14703) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)), [#13846](https://github.com/ClickHouse/ClickHouse/pull/13846) ([hexiaoting](https://github.com/hexiaoting)).
* Add `JSONStrings` format which output data in arrays of strings. [#14333](https://github.com/ClickHouse/ClickHouse/pull/14333) ([hcz](https://github.com/hczhcz)).
* Add support for "Raw" column format for `Regexp` format. It allows to simply extract subpatterns as a whole without any escaping rules. [#15363](https://github.com/ClickHouse/ClickHouse/pull/15363) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Allow configurable `NULL` representation for `TSV` output format. It is controlled by the setting `output_format_tsv_null_representation` which is `\N` by default. This closes [#9375](https://github.com/ClickHouse/ClickHouse/issues/9375). Note that the setting only controls output format and `\N` is the only supported `NULL` representation for `TSV` input format. [#14586](https://github.com/ClickHouse/ClickHouse/pull/14586) ([Kruglov Pavel](https://github.com/Avogar)).
* Support Decimal data type for `MaterializedMySQL`. `MaterializedMySQL` is an experimental feature. [#14535](https://github.com/ClickHouse/ClickHouse/pull/14535) ([Winter Zhang](https://github.com/zhang2014)).
* Add new feature: `SHOW DATABASES LIKE 'xxx'`. [#14521](https://github.com/ClickHouse/ClickHouse/pull/14521) ([hexiaoting](https://github.com/hexiaoting)).
* Added a script to import (arbitrary) git repository to ClickHouse as a sample dataset. [#14471](https://github.com/ClickHouse/ClickHouse/pull/14471) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Now insert statements can have asterisk (or variants) with column transformers in the column list. [#14453](https://github.com/ClickHouse/ClickHouse/pull/14453) ([Amos Bird](https://github.com/amosbird)).
* New query complexity limit settings `max_rows_to_read_leaf`, `max_bytes_to_read_leaf` for distributed queries to limit max rows/bytes read on the leaf nodes. Limit is applied for local reads only, *excluding* the final merge stage on the root node. [#14221](https://github.com/ClickHouse/ClickHouse/pull/14221) ([Roman Khavronenko](https://github.com/hagen1778)).
* Allow user to specify settings for `ReplicatedMergeTree*` storage in `<replicated_merge_tree>` section of config file. It works similarly to `<merge_tree>` section. For `ReplicatedMergeTree*` storages settings from `<merge_tree>` and `<replicated_merge_tree>` are applied together, but settings from `<replicated_merge_tree>` has higher priority. Added `system.replicated_merge_tree_settings` table. [#13573](https://github.com/ClickHouse/ClickHouse/pull/13573) ([Amos Bird](https://github.com/amosbird)).
* Add `mapPopulateSeries` function. [#13166](https://github.com/ClickHouse/ClickHouse/pull/13166) ([Ildus Kurbangaliev](https://github.com/ildus)).
* Supporting MySQL types: `decimal` (as ClickHouse `Decimal`) and `datetime` with sub-second precision (as `DateTime64`). [#11512](https://github.com/ClickHouse/ClickHouse/pull/11512) ([Vasily Nemkov](https://github.com/Enmk)).
* Introduce `event_time_microseconds` field to `system.text_log`, `system.trace_log`, `system.query_log` and `system.query_thread_log` tables. [#14760](https://github.com/ClickHouse/ClickHouse/pull/14760) ([Bharat Nallan](https://github.com/bharatnc)).
* Add `event_time_microseconds` to `system.asynchronous_metric_log` & `system.metric_log` tables. [#14514](https://github.com/ClickHouse/ClickHouse/pull/14514) ([Bharat Nallan](https://github.com/bharatnc)).
* Add `query_start_time_microseconds` field to `system.query_log` & `system.query_thread_log` tables. [#14252](https://github.com/ClickHouse/ClickHouse/pull/14252) ([Bharat Nallan](https://github.com/bharatnc)).
#### Bug Fix
* Fix the case when memory can be overallocated regardless to the limit. This closes [#14560](https://github.com/ClickHouse/ClickHouse/issues/14560). [#16206](https://github.com/ClickHouse/ClickHouse/pull/16206) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix `executable` dictionary source hang. In previous versions, when using some formats (e.g. `JSONEachRow`) data was not feed to a child process before it outputs at least something. This closes [#1697](https://github.com/ClickHouse/ClickHouse/issues/1697). This closes [#2455](https://github.com/ClickHouse/ClickHouse/issues/2455). [#14525](https://github.com/ClickHouse/ClickHouse/pull/14525) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix double free in case of exception in function `dictGet`. It could have happened if dictionary was loaded with error. [#16429](https://github.com/ClickHouse/ClickHouse/pull/16429) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix group by with totals/rollup/cube modifers and min/max functions over group by keys. Fixes [#16393](https://github.com/ClickHouse/ClickHouse/issues/16393). [#16397](https://github.com/ClickHouse/ClickHouse/pull/16397) ([Anton Popov](https://github.com/CurtizJ)).
* Fix async Distributed INSERT with prefer_localhost_replica=0 and internal_replication. [#16358](https://github.com/ClickHouse/ClickHouse/pull/16358) ([Azat Khuzhin](https://github.com/azat)).
* Fix a very wrong code in TwoLevelStringHashTable implementation, which might lead to memory leak. [#16264](https://github.com/ClickHouse/ClickHouse/pull/16264) ([Amos Bird](https://github.com/amosbird)).
* Fix segfault in some cases of wrong aggregation in lambdas. [#16082](https://github.com/ClickHouse/ClickHouse/pull/16082) ([Anton Popov](https://github.com/CurtizJ)).
* Fix `ALTER MODIFY ... ORDER BY` query hang for `ReplicatedVersionedCollapsingMergeTree`. This fixes [#15980](https://github.com/ClickHouse/ClickHouse/issues/15980). [#16011](https://github.com/ClickHouse/ClickHouse/pull/16011) ([alesapin](https://github.com/alesapin)).
* `MaterializedMySQL` (experimental feature): Fix collate name & charset name parser and support `length = 0` for string type. [#16008](https://github.com/ClickHouse/ClickHouse/pull/16008) ([Winter Zhang](https://github.com/zhang2014)).
* Allow to use `direct` layout for dictionaries with complex keys. [#16007](https://github.com/ClickHouse/ClickHouse/pull/16007) ([Anton Popov](https://github.com/CurtizJ)).
* Prevent replica hang for 5-10 mins when replication error happens after a period of inactivity. [#15987](https://github.com/ClickHouse/ClickHouse/pull/15987) ([filimonov](https://github.com/filimonov)).
* Fix rare segfaults when inserting into or selecting from MaterializedView and concurrently dropping target table (for Atomic database engine). [#15984](https://github.com/ClickHouse/ClickHouse/pull/15984) ([tavplubix](https://github.com/tavplubix)).
* Fix ambiguity in parsing of settings profiles: `CREATE USER ... SETTINGS profile readonly` is now considered as using a profile named `readonly`, not a setting named `profile` with the readonly constraint. This fixes [#15628](https://github.com/ClickHouse/ClickHouse/issues/15628). [#15982](https://github.com/ClickHouse/ClickHouse/pull/15982) ([Vitaly Baranov](https://github.com/vitlibar)).
* `MaterializedMySQL` (experimental feature): Fix crash on create database failure. [#15954](https://github.com/ClickHouse/ClickHouse/pull/15954) ([Winter Zhang](https://github.com/zhang2014)).
* Fixed `DROP TABLE IF EXISTS` failure with `Table ... doesn't exist` error when table is concurrently renamed (for Atomic database engine). Fixed rare deadlock when concurrently executing some DDL queries with multiple tables (like `DROP DATABASE` and `RENAME TABLE`) - Fixed `DROP/DETACH DATABASE` failure with `Table ... doesn't exist` when concurrently executing `DROP/DETACH TABLE`. [#15934](https://github.com/ClickHouse/ClickHouse/pull/15934) ([tavplubix](https://github.com/tavplubix)).
* Fix incorrect empty result for query from `Distributed` table if query has `WHERE`, `PREWHERE` and `GLOBAL IN`. Fixes [#15792](https://github.com/ClickHouse/ClickHouse/issues/15792). [#15933](https://github.com/ClickHouse/ClickHouse/pull/15933) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fixes [#12513](https://github.com/ClickHouse/ClickHouse/issues/12513): difference expressions with same alias when query is reanalyzed. [#15886](https://github.com/ClickHouse/ClickHouse/pull/15886) ([Winter Zhang](https://github.com/zhang2014)).
* Fix possible very rare deadlocks in RBAC implementation. [#15875](https://github.com/ClickHouse/ClickHouse/pull/15875) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix exception `Block structure mismatch` in `SELECT ... ORDER BY DESC` queries which were executed after `ALTER MODIFY COLUMN` query. Fixes [#15800](https://github.com/ClickHouse/ClickHouse/issues/15800). [#15852](https://github.com/ClickHouse/ClickHouse/pull/15852) ([alesapin](https://github.com/alesapin)).
* `MaterializedMySQL` (experimental feature): Fix `select count()` inaccuracy. [#15767](https://github.com/ClickHouse/ClickHouse/pull/15767) ([tavplubix](https://github.com/tavplubix)).
* Fix some cases of queries, in which only virtual columns are selected. Previously `Not found column _nothing in block` exception may be thrown. Fixes [#12298](https://github.com/ClickHouse/ClickHouse/issues/12298). [#15756](https://github.com/ClickHouse/ClickHouse/pull/15756) ([Anton Popov](https://github.com/CurtizJ)).
* Fix drop of materialized view with inner table in Atomic database (hangs all subsequent DROP TABLE due to hang of the worker thread, due to recursive DROP TABLE for inner table of MV). [#15743](https://github.com/ClickHouse/ClickHouse/pull/15743) ([Azat Khuzhin](https://github.com/azat)).
* Possibility to move part to another disk/volume if the first attempt was failed. [#15723](https://github.com/ClickHouse/ClickHouse/pull/15723) ([Pavel Kovalenko](https://github.com/Jokser)).
* Fix error `Cannot find column` which may happen at insertion into `MATERIALIZED VIEW` in case if query for `MV` containes `ARRAY JOIN`. [#15717](https://github.com/ClickHouse/ClickHouse/pull/15717) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fixed too low default value of `max_replicated_logs_to_keep` setting, which might cause replicas to become lost too often. Improve lost replica recovery process by choosing the most up-to-date replica to clone. Also do not remove old parts from lost replica, detach them instead. [#15701](https://github.com/ClickHouse/ClickHouse/pull/15701) ([tavplubix](https://github.com/tavplubix)).
* Fix rare race condition in dictionaries and tables from MySQL. [#15686](https://github.com/ClickHouse/ClickHouse/pull/15686) ([alesapin](https://github.com/alesapin)).
* Fix (benign) race condition in AMQP-CPP. [#15667](https://github.com/ClickHouse/ClickHouse/pull/15667) ([alesapin](https://github.com/alesapin)).
* Fix error `Cannot add simple transform to empty Pipe` which happened while reading from `Buffer` table which has different structure than destination table. It was possible if destination table returned empty result for query. Fixes [#15529](https://github.com/ClickHouse/ClickHouse/issues/15529). [#15662](https://github.com/ClickHouse/ClickHouse/pull/15662) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Proper error handling during insert into MergeTree with S3. MergeTree over S3 is an experimental feature. [#15657](https://github.com/ClickHouse/ClickHouse/pull/15657) ([Pavel Kovalenko](https://github.com/Jokser)).
* Fixed bug with S3 table function: region from URL was not applied to S3 client configuration. [#15646](https://github.com/ClickHouse/ClickHouse/pull/15646) ([Vladimir Chebotarev](https://github.com/excitoon)).
* Fix the order of destruction for resources in `ReadFromStorage` step of query plan. It might cause crashes in rare cases. Possibly connected with [#15610](https://github.com/ClickHouse/ClickHouse/issues/15610). [#15645](https://github.com/ClickHouse/ClickHouse/pull/15645) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Subtract `ReadonlyReplica` metric when detach readonly tables. [#15592](https://github.com/ClickHouse/ClickHouse/pull/15592) ([sundyli](https://github.com/sundy-li)).
* Fixed `Element ... is not a constant expression` error when using `JSON*` function result in `VALUES`, `LIMIT` or right side of `IN` operator. [#15589](https://github.com/ClickHouse/ClickHouse/pull/15589) ([tavplubix](https://github.com/tavplubix)).
* Query will finish faster in case of exception. Cancel execution on remote replicas if exception happens. [#15578](https://github.com/ClickHouse/ClickHouse/pull/15578) ([Azat Khuzhin](https://github.com/azat)).
* Prevent the possibility of error message `Could not calculate available disk space (statvfs), errno: 4, strerror: Interrupted system call`. This fixes [#15541](https://github.com/ClickHouse/ClickHouse/issues/15541). [#15557](https://github.com/ClickHouse/ClickHouse/pull/15557) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix `Database <db> doesn't exist.` in queries with IN and Distributed table when there's no database on initiator. [#15538](https://github.com/ClickHouse/ClickHouse/pull/15538) ([Artem Zuikov](https://github.com/4ertus2)).
* Mutation might hang waiting for some non-existent part after `MOVE` or `REPLACE PARTITION` or, in rare cases, after `DETACH` or `DROP PARTITION`. It's fixed. [#15537](https://github.com/ClickHouse/ClickHouse/pull/15537) ([tavplubix](https://github.com/tavplubix)).
* Fix bug when `ILIKE` operator stops being case insensitive if `LIKE` with the same pattern was executed. [#15536](https://github.com/ClickHouse/ClickHouse/pull/15536) ([alesapin](https://github.com/alesapin)).
* Fix `Missing columns` errors when selecting columns which absent in data, but depend on other columns which also absent in data. Fixes [#15530](https://github.com/ClickHouse/ClickHouse/issues/15530). [#15532](https://github.com/ClickHouse/ClickHouse/pull/15532) ([alesapin](https://github.com/alesapin)).
* Throw an error when a single parameter is passed to ReplicatedMergeTree instead of ignoring it. [#15516](https://github.com/ClickHouse/ClickHouse/pull/15516) ([nvartolomei](https://github.com/nvartolomei)).
* Fix bug with event subscription in DDLWorker which rarely may lead to query hangs in `ON CLUSTER`. Introduced in [#13450](https://github.com/ClickHouse/ClickHouse/issues/13450). [#15477](https://github.com/ClickHouse/ClickHouse/pull/15477) ([alesapin](https://github.com/alesapin)).
* Report proper error when the second argument of `boundingRatio` aggregate function has a wrong type. [#15407](https://github.com/ClickHouse/ClickHouse/pull/15407) ([detailyang](https://github.com/detailyang)).
* Fixes [#15365](https://github.com/ClickHouse/ClickHouse/issues/15365): attach a database with MySQL engine throws exception (no query context). [#15384](https://github.com/ClickHouse/ClickHouse/pull/15384) ([Winter Zhang](https://github.com/zhang2014)).
* Fix the case of multiple occurrences of column transformers in a select query. [#15378](https://github.com/ClickHouse/ClickHouse/pull/15378) ([Amos Bird](https://github.com/amosbird)).
* Fixed compression in `S3` storage. [#15376](https://github.com/ClickHouse/ClickHouse/pull/15376) ([Vladimir Chebotarev](https://github.com/excitoon)).
* Fix bug where queries like `SELECT toStartOfDay(today())` fail complaining about empty time_zone argument. [#15319](https://github.com/ClickHouse/ClickHouse/pull/15319) ([Bharat Nallan](https://github.com/bharatnc)).
* Fix race condition during MergeTree table rename and background cleanup. [#15304](https://github.com/ClickHouse/ClickHouse/pull/15304) ([alesapin](https://github.com/alesapin)).
* Fix rare race condition on server startup when system logs are enabled. [#15300](https://github.com/ClickHouse/ClickHouse/pull/15300) ([alesapin](https://github.com/alesapin)).
* Fix hang of queries with a lot of subqueries to same table of `MySQL` engine. Previously, if there were more than 16 subqueries to same `MySQL` table in query, it hang forever. [#15299](https://github.com/ClickHouse/ClickHouse/pull/15299) ([Anton Popov](https://github.com/CurtizJ)).
* Fix MSan report in QueryLog. Uninitialized memory can be used for the field `memory_usage`. [#15258](https://github.com/ClickHouse/ClickHouse/pull/15258) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix 'Unknown identifier' in GROUP BY when query has JOIN over Merge table. [#15242](https://github.com/ClickHouse/ClickHouse/pull/15242) ([Artem Zuikov](https://github.com/4ertus2)).
* Fix instance crash when using `joinGet` with `LowCardinality` types. This fixes https://github.com/ClickHouse/ClickHouse/issues/15214. [#15220](https://github.com/ClickHouse/ClickHouse/pull/15220) ([Amos Bird](https://github.com/amosbird)).
* Fix bug in table engine `Buffer` which doesn't allow to insert data of new structure into `Buffer` after `ALTER` query. Fixes [#15117](https://github.com/ClickHouse/ClickHouse/issues/15117). [#15192](https://github.com/ClickHouse/ClickHouse/pull/15192) ([alesapin](https://github.com/alesapin)).
* Adjust Decimal field size in MySQL column definition packet. [#15152](https://github.com/ClickHouse/ClickHouse/pull/15152) ([maqroll](https://github.com/maqroll)).
* Fixes `Data compressed with different methods` in `join_algorithm='auto'`. Keep LowCardinality as type for left table join key in `join_algorithm='partial_merge'`. [#15088](https://github.com/ClickHouse/ClickHouse/pull/15088) ([Artem Zuikov](https://github.com/4ertus2)).
* Update `jemalloc` to fix `percpu_arena` with affinity mask. [#15035](https://github.com/ClickHouse/ClickHouse/pull/15035) ([Azat Khuzhin](https://github.com/azat)). [#14957](https://github.com/ClickHouse/ClickHouse/pull/14957) ([Azat Khuzhin](https://github.com/azat)).
* We already use padded comparison between String and FixedString (https://github.com/ClickHouse/ClickHouse/blob/master/src/Functions/FunctionsComparison.h#L333). This PR applies the same logic to field comparison which corrects the usage of FixedString as primary keys. This fixes https://github.com/ClickHouse/ClickHouse/issues/14908. [#15033](https://github.com/ClickHouse/ClickHouse/pull/15033) ([Amos Bird](https://github.com/amosbird)).
* If function `bar` was called with specifically crafted arguments, buffer overflow was possible. This closes [#13926](https://github.com/ClickHouse/ClickHouse/issues/13926). [#15028](https://github.com/ClickHouse/ClickHouse/pull/15028) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fixed `Cannot rename ... errno: 22, strerror: Invalid argument` error on DDL query execution in Atomic database when running clickhouse-server in Docker on Mac OS. [#15024](https://github.com/ClickHouse/ClickHouse/pull/15024) ([tavplubix](https://github.com/tavplubix)).
* Fix crash in RIGHT or FULL JOIN with join_algorith='auto' when memory limit exceeded and we should change HashJoin with MergeJoin. [#15002](https://github.com/ClickHouse/ClickHouse/pull/15002) ([Artem Zuikov](https://github.com/4ertus2)).
* Now settings `number_of_free_entries_in_pool_to_execute_mutation` and `number_of_free_entries_in_pool_to_lower_max_size_of_merge` can be equal to `background_pool_size`. [#14975](https://github.com/ClickHouse/ClickHouse/pull/14975) ([alesapin](https://github.com/alesapin)).
* Fix to make predicate push down work when subquery contains `finalizeAggregation` function. Fixes [#14847](https://github.com/ClickHouse/ClickHouse/issues/14847). [#14937](https://github.com/ClickHouse/ClickHouse/pull/14937) ([filimonov](https://github.com/filimonov)).
* Publish CPU frequencies per logical core in `system.asynchronous_metrics`. This fixes https://github.com/ClickHouse/ClickHouse/issues/14923. [#14924](https://github.com/ClickHouse/ClickHouse/pull/14924) ([Alexander Kuzmenkov](https://github.com/akuzm)).
* `MaterializedMySQL` (experimental feature): Fixed `.metadata.tmp File exists` error. [#14898](https://github.com/ClickHouse/ClickHouse/pull/14898) ([Winter Zhang](https://github.com/zhang2014)).
* Fix the issue when some invocations of `extractAllGroups` function may trigger "Memory limit exceeded" error. This fixes [#13383](https://github.com/ClickHouse/ClickHouse/issues/13383). [#14889](https://github.com/ClickHouse/ClickHouse/pull/14889) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix SIGSEGV for an attempt to INSERT into StorageFile with file descriptor. [#14887](https://github.com/ClickHouse/ClickHouse/pull/14887) ([Azat Khuzhin](https://github.com/azat)).
* Fixed segfault in `cache` dictionary [#14837](https://github.com/ClickHouse/ClickHouse/issues/14837). [#14879](https://github.com/ClickHouse/ClickHouse/pull/14879) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* `MaterializedMySQL` (experimental feature): Fixed bug in parsing MySQL binlog events, which causes `Attempt to read after eof` and `Packet payload is not fully read` in `MaterializeMySQL` database engine. [#14852](https://github.com/ClickHouse/ClickHouse/pull/14852) ([Winter Zhang](https://github.com/zhang2014)).
* Fix rare error in `SELECT` queries when the queried column has `DEFAULT` expression which depends on the other column which also has `DEFAULT` and not present in select query and not exists on disk. Partially fixes [#14531](https://github.com/ClickHouse/ClickHouse/issues/14531). [#14845](https://github.com/ClickHouse/ClickHouse/pull/14845) ([alesapin](https://github.com/alesapin)).
* Fix a problem where the server may get stuck on startup while talking to ZooKeeper, if the configuration files have to be fetched from ZK (using the `from_zk` include option). This fixes [#14814](https://github.com/ClickHouse/ClickHouse/issues/14814). [#14843](https://github.com/ClickHouse/ClickHouse/pull/14843) ([Alexander Kuzmenkov](https://github.com/akuzm)).
* Fix wrong monotonicity detection for shrunk `Int -> Int` cast of signed types. It might lead to incorrect query result. This bug is unveiled in [#14513](https://github.com/ClickHouse/ClickHouse/issues/14513). [#14783](https://github.com/ClickHouse/ClickHouse/pull/14783) ([Amos Bird](https://github.com/amosbird)).
* `Replace` column transformer should replace identifiers with cloned ASTs. This fixes https://github.com/ClickHouse/ClickHouse/issues/14695 . [#14734](https://github.com/ClickHouse/ClickHouse/pull/14734) ([Amos Bird](https://github.com/amosbird)).
* Fixed missed default database name in metadata of materialized view when executing `ALTER ... MODIFY QUERY`. [#14664](https://github.com/ClickHouse/ClickHouse/pull/14664) ([tavplubix](https://github.com/tavplubix)).
* Fix bug when `ALTER UPDATE` mutation with `Nullable` column in assignment expression and constant value (like `UPDATE x = 42`) leads to incorrect value in column or segfault. Fixes [#13634](https://github.com/ClickHouse/ClickHouse/issues/13634), [#14045](https://github.com/ClickHouse/ClickHouse/issues/14045). [#14646](https://github.com/ClickHouse/ClickHouse/pull/14646) ([alesapin](https://github.com/alesapin)).
* Fix wrong Decimal multiplication result caused wrong decimal scale of result column. [#14603](https://github.com/ClickHouse/ClickHouse/pull/14603) ([Artem Zuikov](https://github.com/4ertus2)).
* Fix function `has` with `LowCardinality` of `Nullable`. [#14591](https://github.com/ClickHouse/ClickHouse/pull/14591) ([Mike](https://github.com/myrrc)).
* Cleanup data directory after Zookeeper exceptions during CreateQuery for StorageReplicatedMergeTree Engine. [#14563](https://github.com/ClickHouse/ClickHouse/pull/14563) ([Bharat Nallan](https://github.com/bharatnc)).
* Fix rare segfaults in functions with combinator `-Resample`, which could appear in result of overflow with very large parameters. [#14562](https://github.com/ClickHouse/ClickHouse/pull/14562) ([Anton Popov](https://github.com/CurtizJ)).
* Fix a bug when converting `Nullable(String)` to Enum. Introduced by https://github.com/ClickHouse/ClickHouse/pull/12745. This fixes https://github.com/ClickHouse/ClickHouse/issues/14435. [#14530](https://github.com/ClickHouse/ClickHouse/pull/14530) ([Amos Bird](https://github.com/amosbird)).
* Fixed the incorrect sorting order of `Nullable` column. This fixes [#14344](https://github.com/ClickHouse/ClickHouse/issues/14344). [#14495](https://github.com/ClickHouse/ClickHouse/pull/14495) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Fix `currentDatabase()` function cannot be used in `ON CLUSTER` ddl query. [#14211](https://github.com/ClickHouse/ClickHouse/pull/14211) ([Winter Zhang](https://github.com/zhang2014)).
* `MaterializedMySQL` (experimental feature): Fixed `Packet payload is not fully read` error in `MaterializeMySQL` database engine. [#14696](https://github.com/ClickHouse/ClickHouse/pull/14696) ([BohuTANG](https://github.com/BohuTANG)).
#### Improvement
* Enable `Atomic` database engine by default for newly created databases. [#15003](https://github.com/ClickHouse/ClickHouse/pull/15003) ([tavplubix](https://github.com/tavplubix)).
* Add the ability to specify specialized codecs like `Delta`, `T64`, etc. for columns with subtypes. Implements [#12551](https://github.com/ClickHouse/ClickHouse/issues/12551), fixes [#11397](https://github.com/ClickHouse/ClickHouse/issues/11397), fixes [#4609](https://github.com/ClickHouse/ClickHouse/issues/4609). [#15089](https://github.com/ClickHouse/ClickHouse/pull/15089) ([alesapin](https://github.com/alesapin)).
* Dynamic reload of zookeeper config. [#14678](https://github.com/ClickHouse/ClickHouse/pull/14678) ([sundyli](https://github.com/sundy-li)).
* Now it's allowed to execute `ALTER ... ON CLUSTER` queries regardless of the `<internal_replication>` setting in cluster config. [#16075](https://github.com/ClickHouse/ClickHouse/pull/16075) ([alesapin](https://github.com/alesapin)).
* Now `joinGet` supports multi-key lookup. Continuation of [#12418](https://github.com/ClickHouse/ClickHouse/issues/12418). [#13015](https://github.com/ClickHouse/ClickHouse/pull/13015) ([Amos Bird](https://github.com/amosbird)).
* Wait for `DROP/DETACH TABLE` to actually finish if `NO DELAY` or `SYNC` is specified for `Atomic` database. [#15448](https://github.com/ClickHouse/ClickHouse/pull/15448) ([tavplubix](https://github.com/tavplubix)).
* Now it's possible to change the type of version column for `VersionedCollapsingMergeTree` with `ALTER` query. [#15442](https://github.com/ClickHouse/ClickHouse/pull/15442) ([alesapin](https://github.com/alesapin)).
* Unfold `{database}`, `{table}` and `{uuid}` macros in `zookeeper_path` on replicated table creation. Do not allow `RENAME TABLE` if it may break `zookeeper_path` after server restart. Fixes [#6917](https://github.com/ClickHouse/ClickHouse/issues/6917). [#15348](https://github.com/ClickHouse/ClickHouse/pull/15348) ([tavplubix](https://github.com/tavplubix)).
* The function `now` allows an argument with timezone. This closes [15264](https://github.com/ClickHouse/ClickHouse/issues/15264). [#15285](https://github.com/ClickHouse/ClickHouse/pull/15285) ([flynn](https://github.com/ucasFL)).
* Do not allow connections to ClickHouse server until all scripts in `/docker-entrypoint-initdb.d/` are executed. [#15244](https://github.com/ClickHouse/ClickHouse/pull/15244) ([Aleksei Kozharin](https://github.com/alekseik1)).
* Added `optimize` setting to `EXPLAIN PLAN` query. If enabled, query plan level optimisations are applied. Enabled by default. [#15201](https://github.com/ClickHouse/ClickHouse/pull/15201) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Proper exception message for wrong number of arguments of CAST. This closes [#13992](https://github.com/ClickHouse/ClickHouse/issues/13992). [#15029](https://github.com/ClickHouse/ClickHouse/pull/15029) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add option to disable TTL move on data part insert. [#15000](https://github.com/ClickHouse/ClickHouse/pull/15000) ([Pavel Kovalenko](https://github.com/Jokser)).
* Ignore key constraints when doing mutations. Without this pull request, it's not possible to do mutations when `force_index_by_date = 1` or `force_primary_key = 1`. [#14973](https://github.com/ClickHouse/ClickHouse/pull/14973) ([Amos Bird](https://github.com/amosbird)).
* Allow to drop Replicated table if previous drop attempt was failed due to ZooKeeper session expiration. This fixes [#11891](https://github.com/ClickHouse/ClickHouse/issues/11891). [#14926](https://github.com/ClickHouse/ClickHouse/pull/14926) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fixed excessive settings constraint violation when running SELECT with SETTINGS from a distributed table. [#14876](https://github.com/ClickHouse/ClickHouse/pull/14876) ([Amos Bird](https://github.com/amosbird)).
* Provide a `load_balancing_first_offset` query setting to explicitly state what the first replica is. It's used together with `FIRST_OR_RANDOM` load balancing strategy, which allows to control replicas workload. [#14867](https://github.com/ClickHouse/ClickHouse/pull/14867) ([Amos Bird](https://github.com/amosbird)).
* Show subqueries for `SET` and `JOIN` in `EXPLAIN` result. [#14856](https://github.com/ClickHouse/ClickHouse/pull/14856) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Allow using multi-volume storage configuration in storage `Distributed`. [#14839](https://github.com/ClickHouse/ClickHouse/pull/14839) ([Pavel Kovalenko](https://github.com/Jokser)).
* Construct `query_start_time` and `query_start_time_microseconds` from the same timespec. [#14831](https://github.com/ClickHouse/ClickHouse/pull/14831) ([Bharat Nallan](https://github.com/bharatnc)).
* Support for disabling persistency for `StorageJoin` and `StorageSet`, this feature is controlled by setting `disable_set_and_join_persistency`. And this PR solved issue [#6318](https://github.com/ClickHouse/ClickHouse/issues/6318). [#14776](https://github.com/ClickHouse/ClickHouse/pull/14776) ([vxider](https://github.com/Vxider)).
* Now `COLUMNS` can be used to wrap over a list of columns and apply column transformers afterwards. [#14775](https://github.com/ClickHouse/ClickHouse/pull/14775) ([Amos Bird](https://github.com/amosbird)).
* Add `merge_algorithm` to `system.merges` table to improve merging inspections. [#14705](https://github.com/ClickHouse/ClickHouse/pull/14705) ([Amos Bird](https://github.com/amosbird)).
* Fix potential memory leak caused by zookeeper exists watch. [#14693](https://github.com/ClickHouse/ClickHouse/pull/14693) ([hustnn](https://github.com/hustnn)).
* Allow parallel execution of distributed DDL. [#14684](https://github.com/ClickHouse/ClickHouse/pull/14684) ([Azat Khuzhin](https://github.com/azat)).
* Add `QueryMemoryLimitExceeded` event counter. This closes [#14589](https://github.com/ClickHouse/ClickHouse/issues/14589). [#14647](https://github.com/ClickHouse/ClickHouse/pull/14647) ([fastio](https://github.com/fastio)).
* Fix some trailing whitespaces in query formatting. [#14595](https://github.com/ClickHouse/ClickHouse/pull/14595) ([Azat Khuzhin](https://github.com/azat)).
* ClickHouse treats partition expr and key expr differently. Partition expr is used to construct an minmax index containing related columns, while primary key expr is stored as an expr. Sometimes user might partition a table at coarser levels, such as `partition by i / 1000`. However, binary operators are not monotonic and this PR tries to fix that. It might also benifit other use cases. [#14513](https://github.com/ClickHouse/ClickHouse/pull/14513) ([Amos Bird](https://github.com/amosbird)).
* Add an option to skip access checks for `DiskS3`. `s3` disk is an experimental feature. [#14497](https://github.com/ClickHouse/ClickHouse/pull/14497) ([Pavel Kovalenko](https://github.com/Jokser)).
* Speed up server shutdown process if there are ongoing S3 requests. [#14496](https://github.com/ClickHouse/ClickHouse/pull/14496) ([Pavel Kovalenko](https://github.com/Jokser)).
* `SYSTEM RELOAD CONFIG` now throws an exception if failed to reload and continues using the previous users.xml. The background periodic reloading also continues using the previous users.xml if failed to reload. [#14492](https://github.com/ClickHouse/ClickHouse/pull/14492) ([Vitaly Baranov](https://github.com/vitlibar)).
* For INSERTs with inline data in VALUES format in the script mode of `clickhouse-client`, support semicolon as the data terminator, in addition to the new line. Closes https://github.com/ClickHouse/ClickHouse/issues/12288. [#13192](https://github.com/ClickHouse/ClickHouse/pull/13192) ([Alexander Kuzmenkov](https://github.com/akuzm)).
* Support custom codecs in compact parts. [#12183](https://github.com/ClickHouse/ClickHouse/pull/12183) ([Anton Popov](https://github.com/CurtizJ)).
#### Performance Improvement
* Enable compact parts by default for small parts. This will allow to process frequent inserts slightly more efficiently (4..100 times). [#11913](https://github.com/ClickHouse/ClickHouse/pull/11913) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Improve `quantileTDigest` performance. This fixes [#2668](https://github.com/ClickHouse/ClickHouse/issues/2668). [#15542](https://github.com/ClickHouse/ClickHouse/pull/15542) ([Kruglov Pavel](https://github.com/Avogar)).
* Significantly reduce memory usage in AggregatingInOrderTransform/optimize_aggregation_in_order. [#15543](https://github.com/ClickHouse/ClickHouse/pull/15543) ([Azat Khuzhin](https://github.com/azat)).
* Faster 256-bit multiplication. [#15418](https://github.com/ClickHouse/ClickHouse/pull/15418) ([Artem Zuikov](https://github.com/4ertus2)).
* Improve performance of 256-bit types using (u)int64_t as base type for wide integers. Original wide integers use 8-bit types as base. [#14859](https://github.com/ClickHouse/ClickHouse/pull/14859) ([Artem Zuikov](https://github.com/4ertus2)).
* Explicitly use a temporary disk to store vertical merge temporary data. [#15639](https://github.com/ClickHouse/ClickHouse/pull/15639) ([Grigory Pervakov](https://github.com/GrigoryPervakov)).
* Use one S3 DeleteObjects request instead of multiple DeleteObject in a loop. No any functionality changes, so covered by existing tests like integration/test_log_family_s3. [#15238](https://github.com/ClickHouse/ClickHouse/pull/15238) ([ianton-ru](https://github.com/ianton-ru)).
* Fix `DateTime <op> DateTime` mistakenly choosing the slow generic implementation. This fixes https://github.com/ClickHouse/ClickHouse/issues/15153. [#15178](https://github.com/ClickHouse/ClickHouse/pull/15178) ([Amos Bird](https://github.com/amosbird)).
* Improve performance of GROUP BY key of type `FixedString`. [#15034](https://github.com/ClickHouse/ClickHouse/pull/15034) ([Amos Bird](https://github.com/amosbird)).
* Only `mlock` code segment when starting clickhouse-server. In previous versions, all mapped regions were locked in memory, including debug info. Debug info is usually splitted to a separate file but if it isn't, it led to +2..3 GiB memory usage. [#14929](https://github.com/ClickHouse/ClickHouse/pull/14929) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* ClickHouse binary become smaller due to link time optimization.
#### Build/Testing/Packaging Improvement
* Now we use clang-11 for production ClickHouse build. [#15239](https://github.com/ClickHouse/ClickHouse/pull/15239) ([alesapin](https://github.com/alesapin)).
* Now we use clang-11 to build ClickHouse in CI. [#14846](https://github.com/ClickHouse/ClickHouse/pull/14846) ([alesapin](https://github.com/alesapin)).
* Switch binary builds (Linux, Darwin, AArch64, FreeDSD) to clang-11. [#15622](https://github.com/ClickHouse/ClickHouse/pull/15622) ([Ilya Yatsishin](https://github.com/qoega)).
* Now all test images use `llvm-symbolizer-11`. [#15069](https://github.com/ClickHouse/ClickHouse/pull/15069) ([alesapin](https://github.com/alesapin)).
* Allow to build with llvm-11. [#15366](https://github.com/ClickHouse/ClickHouse/pull/15366) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Switch from `clang-tidy-10` to `clang-tidy-11`. [#14922](https://github.com/ClickHouse/ClickHouse/pull/14922) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Use LLVM's experimental pass manager by default. [#15608](https://github.com/ClickHouse/ClickHouse/pull/15608) ([Danila Kutenin](https://github.com/danlark1)).
* Don't allow any C++ translation unit to build more than 10 minutes or to use more than 10 GB or memory. This fixes [#14925](https://github.com/ClickHouse/ClickHouse/issues/14925). [#15060](https://github.com/ClickHouse/ClickHouse/pull/15060) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Make performance test more stable and representative by splitting test runs and profile runs. [#15027](https://github.com/ClickHouse/ClickHouse/pull/15027) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Attempt to make performance test more reliable. It is done by remapping the executable memory of the process on the fly with `madvise` to use transparent huge pages - it can lower the number of iTLB misses which is the main source of instabilities in performance tests. [#14685](https://github.com/ClickHouse/ClickHouse/pull/14685) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Convert to python3. This closes [#14886](https://github.com/ClickHouse/ClickHouse/issues/14886). [#15007](https://github.com/ClickHouse/ClickHouse/pull/15007) ([Azat Khuzhin](https://github.com/azat)).
* Fail early in functional tests if server failed to respond. This closes [#15262](https://github.com/ClickHouse/ClickHouse/issues/15262). [#15267](https://github.com/ClickHouse/ClickHouse/pull/15267) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Allow to run AArch64 version of clickhouse-server without configs. This facilitates [#15174](https://github.com/ClickHouse/ClickHouse/issues/15174). [#15266](https://github.com/ClickHouse/ClickHouse/pull/15266) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Improvements in CI docker images: get rid of ZooKeeper and single script for test configs installation. [#15215](https://github.com/ClickHouse/ClickHouse/pull/15215) ([alesapin](https://github.com/alesapin)).
* Fix CMake options forwarding in fast test script. Fixes error in [#14711](https://github.com/ClickHouse/ClickHouse/issues/14711). [#15155](https://github.com/ClickHouse/ClickHouse/pull/15155) ([alesapin](https://github.com/alesapin)).
* Added a script to perform hardware benchmark in a single command. [#15115](https://github.com/ClickHouse/ClickHouse/pull/15115) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Splitted huge test `test_dictionaries_all_layouts_and_sources` into smaller ones. [#15110](https://github.com/ClickHouse/ClickHouse/pull/15110) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Maybe fix MSan report in base64 (on servers with AVX-512). This fixes [#14006](https://github.com/ClickHouse/ClickHouse/issues/14006). [#15030](https://github.com/ClickHouse/ClickHouse/pull/15030) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Reformat and cleanup code in all integration test *.py files. [#14864](https://github.com/ClickHouse/ClickHouse/pull/14864) ([Bharat Nallan](https://github.com/bharatnc)).
* Fix MaterializeMySQL empty transaction unstable test case found in CI. [#14854](https://github.com/ClickHouse/ClickHouse/pull/14854) ([Winter Zhang](https://github.com/zhang2014)).
* Attempt to speed up build a little. [#14808](https://github.com/ClickHouse/ClickHouse/pull/14808) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Speed up build a little by removing unused headers. [#14714](https://github.com/ClickHouse/ClickHouse/pull/14714) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix build failure in OSX. [#14761](https://github.com/ClickHouse/ClickHouse/pull/14761) ([Winter Zhang](https://github.com/zhang2014)).
* Enable ccache by default in cmake if it's found in OS. [#14575](https://github.com/ClickHouse/ClickHouse/pull/14575) ([alesapin](https://github.com/alesapin)).
* Control CI builds configuration from the ClickHouse repository. [#14547](https://github.com/ClickHouse/ClickHouse/pull/14547) ([alesapin](https://github.com/alesapin)).
* In CMake files: - Moved some options' descriptions' parts to comments above. - Replace 0 -> `OFF`, 1 -> `ON` in `option`s default values. - Added some descriptions and links to docs to the options. - Replaced `FUZZER` option (there is another option `ENABLE_FUZZING` which also enables same functionality). - Removed `ENABLE_GTEST_LIBRARY` option as there is `ENABLE_TESTS`. See the full description in PR: [#14711](https://github.com/ClickHouse/ClickHouse/pull/14711) ([Mike](https://github.com/myrrc)).
* Make binary a bit smaller (~50 Mb for debug version). [#14555](https://github.com/ClickHouse/ClickHouse/pull/14555) ([Artem Zuikov](https://github.com/4ertus2)).
* Use std::filesystem::path in ConfigProcessor for concatenating file paths. [#14558](https://github.com/ClickHouse/ClickHouse/pull/14558) ([Bharat Nallan](https://github.com/bharatnc)).
* Fix debug assertion in `bitShiftLeft()` when called with negative big integer. [#14697](https://github.com/ClickHouse/ClickHouse/pull/14697) ([Artem Zuikov](https://github.com/4ertus2)).
## ClickHouse release 20.9
### ClickHouse release v20.9.5.5-stable, 2020-11-13
#### Bug Fix
* Fix rare silent crashes when query profiler is on and ClickHouse is installed on OS with glibc version that has (supposedly) broken asynchronous unwind tables for some functions. This fixes [#15301](https://github.com/ClickHouse/ClickHouse/issues/15301). This fixes [#13098](https://github.com/ClickHouse/ClickHouse/issues/13098). [#16846](https://github.com/ClickHouse/ClickHouse/pull/16846) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Now when parsing AVRO from input the LowCardinality is removed from type. Fixes [#16188](https://github.com/ClickHouse/ClickHouse/issues/16188). [#16521](https://github.com/ClickHouse/ClickHouse/pull/16521) ([Mike](https://github.com/myrrc)).
* Fix rapid growth of metadata when using MySQL Master -> MySQL Slave -> ClickHouse MaterializeMySQL Engine, and `slave_parallel_worker` enabled on MySQL Slave, by properly shrinking GTID sets. This fixes [#15951](https://github.com/ClickHouse/ClickHouse/issues/15951). [#16504](https://github.com/ClickHouse/ClickHouse/pull/16504) ([TCeason](https://github.com/TCeason)).
* Fix DROP TABLE for Distributed (racy with INSERT). [#16409](https://github.com/ClickHouse/ClickHouse/pull/16409) ([Azat Khuzhin](https://github.com/azat)).
* Fix processing of very large entries in replication queue. Very large entries may appear in ALTER queries if table structure is extremely large (near 1 MB). This fixes [#16307](https://github.com/ClickHouse/ClickHouse/issues/16307). [#16332](https://github.com/ClickHouse/ClickHouse/pull/16332) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fixed the inconsistent behaviour when a part of return data could be dropped because the set for its filtration wasn't created. [#16308](https://github.com/ClickHouse/ClickHouse/pull/16308) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Fix bug with MySQL database. When MySQL server used as database engine is down some queries raise Exception, because they try to get tables from disabled server, while it's unnecessary. For example, query `SELECT ... FROM system.parts` should work only with MergeTree tables and don't touch MySQL database at all. [#16032](https://github.com/ClickHouse/ClickHouse/pull/16032) ([Kruglov Pavel](https://github.com/Avogar)).
### ClickHouse release v20.9.4.76-stable (2020-10-29)
#### Bug Fix
* Fix double free in case of exception in function `dictGet`. It could have happened if dictionary was loaded with error. [#16429](https://github.com/ClickHouse/ClickHouse/pull/16429) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix group by with totals/rollup/cube modifers and min/max functions over group by keys. Fixes [#16393](https://github.com/ClickHouse/ClickHouse/issues/16393). [#16397](https://github.com/ClickHouse/ClickHouse/pull/16397) ([Anton Popov](https://github.com/CurtizJ)).
* Fix async Distributed INSERT w/ prefer_localhost_replica=0 and internal_replication. [#16358](https://github.com/ClickHouse/ClickHouse/pull/16358) ([Azat Khuzhin](https://github.com/azat)).
* Fix a very wrong code in TwoLevelStringHashTable implementation, which might lead to memory leak. I'm suprised how this bug can lurk for so long.... [#16264](https://github.com/ClickHouse/ClickHouse/pull/16264) ([Amos Bird](https://github.com/amosbird)).
* Fix the case when memory can be overallocated regardless to the limit. This closes [#14560](https://github.com/ClickHouse/ClickHouse/issues/14560). [#16206](https://github.com/ClickHouse/ClickHouse/pull/16206) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix `ALTER MODIFY ... ORDER BY` query hang for `ReplicatedVersionedCollapsingMergeTree`. This fixes [#15980](https://github.com/ClickHouse/ClickHouse/issues/15980). [#16011](https://github.com/ClickHouse/ClickHouse/pull/16011) ([alesapin](https://github.com/alesapin)).
* Fix collate name & charset name parser and support `length = 0` for string type. [#16008](https://github.com/ClickHouse/ClickHouse/pull/16008) ([Winter Zhang](https://github.com/zhang2014)).
* Allow to use direct layout for dictionaries with complex keys. [#16007](https://github.com/ClickHouse/ClickHouse/pull/16007) ([Anton Popov](https://github.com/CurtizJ)).
* Prevent replica hang for 5-10 mins when replication error happens after a period of inactivity. [#15987](https://github.com/ClickHouse/ClickHouse/pull/15987) ([filimonov](https://github.com/filimonov)).
* Fix rare segfaults when inserting into or selecting from MaterializedView and concurrently dropping target table (for Atomic database engine). [#15984](https://github.com/ClickHouse/ClickHouse/pull/15984) ([tavplubix](https://github.com/tavplubix)).
* Fix ambiguity in parsing of settings profiles: `CREATE USER ... SETTINGS profile readonly` is now considered as using a profile named `readonly`, not a setting named `profile` with the readonly constraint. This fixes https://github.com/ClickHouse/ClickHouse/issues/15628. [#15982](https://github.com/ClickHouse/ClickHouse/pull/15982) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix a crash when database creation fails. [#15954](https://github.com/ClickHouse/ClickHouse/pull/15954) ([Winter Zhang](https://github.com/zhang2014)).
* Fixed `DROP TABLE IF EXISTS` failure with `Table ... doesn't exist` error when table is concurrently renamed (for Atomic database engine). Fixed rare deadlock when concurrently executing some DDL queries with multiple tables (like `DROP DATABASE` and `RENAME TABLE`) Fixed `DROP/DETACH DATABASE` failure with `Table ... doesn't exist` when concurrently executing `DROP/DETACH TABLE`. [#15934](https://github.com/ClickHouse/ClickHouse/pull/15934) ([tavplubix](https://github.com/tavplubix)).
* Fix incorrect empty result for query from `Distributed` table if query has `WHERE`, `PREWHERE` and `GLOBAL IN`. Fixes [#15792](https://github.com/ClickHouse/ClickHouse/issues/15792). [#15933](https://github.com/ClickHouse/ClickHouse/pull/15933) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix possible deadlocks in RBAC. [#15875](https://github.com/ClickHouse/ClickHouse/pull/15875) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix exception `Block structure mismatch` in `SELECT ... ORDER BY DESC` queries which were executed after `ALTER MODIFY COLUMN` query. Fixes [#15800](https://github.com/ClickHouse/ClickHouse/issues/15800). [#15852](https://github.com/ClickHouse/ClickHouse/pull/15852) ([alesapin](https://github.com/alesapin)).
* Fix `select count()` inaccuracy for MaterializeMySQL. [#15767](https://github.com/ClickHouse/ClickHouse/pull/15767) ([tavplubix](https://github.com/tavplubix)).
* Fix some cases of queries, in which only virtual columns are selected. Previously `Not found column _nothing in block` exception may be thrown. Fixes [#12298](https://github.com/ClickHouse/ClickHouse/issues/12298). [#15756](https://github.com/ClickHouse/ClickHouse/pull/15756) ([Anton Popov](https://github.com/CurtizJ)).
* Fixed too low default value of `max_replicated_logs_to_keep` setting, which might cause replicas to become lost too often. Improve lost replica recovery process by choosing the most up-to-date replica to clone. Also do not remove old parts from lost replica, detach them instead. [#15701](https://github.com/ClickHouse/ClickHouse/pull/15701) ([tavplubix](https://github.com/tavplubix)).
* Fix error `Cannot add simple transform to empty Pipe` which happened while reading from `Buffer` table which has different structure than destination table. It was possible if destination table returned empty result for query. Fixes [#15529](https://github.com/ClickHouse/ClickHouse/issues/15529). [#15662](https://github.com/ClickHouse/ClickHouse/pull/15662) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fixed bug with globs in S3 table function, region from URL was not applied to S3 client configuration. [#15646](https://github.com/ClickHouse/ClickHouse/pull/15646) ([Vladimir Chebotarev](https://github.com/excitoon)).
* Decrement the `ReadonlyReplica` metric when detaching read-only tables. This fixes https://github.com/ClickHouse/ClickHouse/issues/15598. [#15592](https://github.com/ClickHouse/ClickHouse/pull/15592) ([sundyli](https://github.com/sundy-li)).
* Throw an error when a single parameter is passed to ReplicatedMergeTree instead of ignoring it. [#15516](https://github.com/ClickHouse/ClickHouse/pull/15516) ([nvartolomei](https://github.com/nvartolomei)).
#### Improvement
* Now it's allowed to execute `ALTER ... ON CLUSTER` queries regardless of the `<internal_replication>` setting in cluster config. [#16075](https://github.com/ClickHouse/ClickHouse/pull/16075) ([alesapin](https://github.com/alesapin)).
* Unfold `{database}`, `{table}` and `{uuid}` macros in `ReplicatedMergeTree` arguments on table creation. [#16160](https://github.com/ClickHouse/ClickHouse/pull/16160) ([tavplubix](https://github.com/tavplubix)).
### ClickHouse release v20.9.3.45-stable (2020-10-09)
#### Bug Fix
* Fix error `Cannot find column` which may happen at insertion into `MATERIALIZED VIEW` in case if query for `MV` containes `ARRAY JOIN`. [#15717](https://github.com/ClickHouse/ClickHouse/pull/15717) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix race condition in AMQP-CPP. [#15667](https://github.com/ClickHouse/ClickHouse/pull/15667) ([alesapin](https://github.com/alesapin)).
* Fix the order of destruction for resources in `ReadFromStorage` step of query plan. It might cause crashes in rare cases. Possibly connected with [#15610](https://github.com/ClickHouse/ClickHouse/issues/15610). [#15645](https://github.com/ClickHouse/ClickHouse/pull/15645) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fixed `Element ... is not a constant expression` error when using `JSON*` function result in `VALUES`, `LIMIT` or right side of `IN` operator. [#15589](https://github.com/ClickHouse/ClickHouse/pull/15589) ([tavplubix](https://github.com/tavplubix)).
* Prevent the possibility of error message `Could not calculate available disk space (statvfs), errno: 4, strerror: Interrupted system call`. This fixes [#15541](https://github.com/ClickHouse/ClickHouse/issues/15541). [#15557](https://github.com/ClickHouse/ClickHouse/pull/15557) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Significantly reduce memory usage in AggregatingInOrderTransform/optimize_aggregation_in_order. [#15543](https://github.com/ClickHouse/ClickHouse/pull/15543) ([Azat Khuzhin](https://github.com/azat)).
* Mutation might hang waiting for some non-existent part after `MOVE` or `REPLACE PARTITION` or, in rare cases, after `DETACH` or `DROP PARTITION`. It's fixed. [#15537](https://github.com/ClickHouse/ClickHouse/pull/15537) ([tavplubix](https://github.com/tavplubix)).
* Fix bug when `ILIKE` operator stops being case insensitive if `LIKE` with the same pattern was executed. [#15536](https://github.com/ClickHouse/ClickHouse/pull/15536) ([alesapin](https://github.com/alesapin)).
* Fix `Missing columns` errors when selecting columns which absent in data, but depend on other columns which also absent in data. Fixes [#15530](https://github.com/ClickHouse/ClickHouse/issues/15530). [#15532](https://github.com/ClickHouse/ClickHouse/pull/15532) ([alesapin](https://github.com/alesapin)).
* Fix bug with event subscription in DDLWorker which rarely may lead to query hangs in `ON CLUSTER`. Introduced in [#13450](https://github.com/ClickHouse/ClickHouse/issues/13450). [#15477](https://github.com/ClickHouse/ClickHouse/pull/15477) ([alesapin](https://github.com/alesapin)).
* Report proper error when the second argument of `boundingRatio` aggregate function has a wrong type. [#15407](https://github.com/ClickHouse/ClickHouse/pull/15407) ([detailyang](https://github.com/detailyang)).
* Fix bug where queries like SELECT toStartOfDay(today()) fail complaining about empty time_zone argument. [#15319](https://github.com/ClickHouse/ClickHouse/pull/15319) ([Bharat Nallan](https://github.com/bharatnc)).
* Fix race condition during MergeTree table rename and background cleanup. [#15304](https://github.com/ClickHouse/ClickHouse/pull/15304) ([alesapin](https://github.com/alesapin)).
* Fix rare race condition on server startup when system.logs are enabled. [#15300](https://github.com/ClickHouse/ClickHouse/pull/15300) ([alesapin](https://github.com/alesapin)).
* Fix MSan report in QueryLog. Uninitialized memory can be used for the field `memory_usage`. [#15258](https://github.com/ClickHouse/ClickHouse/pull/15258) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix instance crash when using joinGet with LowCardinality types. This fixes https://github.com/ClickHouse/ClickHouse/issues/15214. [#15220](https://github.com/ClickHouse/ClickHouse/pull/15220) ([Amos Bird](https://github.com/amosbird)).
* Fix bug in table engine `Buffer` which doesn't allow to insert data of new structure into `Buffer` after `ALTER` query. Fixes [#15117](https://github.com/ClickHouse/ClickHouse/issues/15117). [#15192](https://github.com/ClickHouse/ClickHouse/pull/15192) ([alesapin](https://github.com/alesapin)).
* Adjust decimals field size in mysql column definition packet. [#15152](https://github.com/ClickHouse/ClickHouse/pull/15152) ([maqroll](https://github.com/maqroll)).
* Fixed `Cannot rename ... errno: 22, strerror: Invalid argument` error on DDL query execution in Atomic database when running clickhouse-server in docker on Mac OS. [#15024](https://github.com/ClickHouse/ClickHouse/pull/15024) ([tavplubix](https://github.com/tavplubix)).
* Fix to make predicate push down work when subquery contains finalizeAggregation function. Fixes [#14847](https://github.com/ClickHouse/ClickHouse/issues/14847). [#14937](https://github.com/ClickHouse/ClickHouse/pull/14937) ([filimonov](https://github.com/filimonov)).
* Fix a problem where the server may get stuck on startup while talking to ZooKeeper, if the configuration files have to be fetched from ZK (using the `from_zk` include option). This fixes [#14814](https://github.com/ClickHouse/ClickHouse/issues/14814). [#14843](https://github.com/ClickHouse/ClickHouse/pull/14843) ([Alexander Kuzmenkov](https://github.com/akuzm)).
#### Improvement
* Now it's possible to change the type of version column for `VersionedCollapsingMergeTree` with `ALTER` query. [#15442](https://github.com/ClickHouse/ClickHouse/pull/15442) ([alesapin](https://github.com/alesapin)).
### ClickHouse release v20.9.2.20, 2020-09-22
#### New Feature
* Added column transformers `EXCEPT`, `REPLACE`, `APPLY`, which can be applied to the list of selected columns (after `*` or `COLUMNS(...)`). For example, you can write `SELECT * EXCEPT(URL) REPLACE(number + 1 AS number)`. Another example: `select * apply(length) apply(max) from wide_string_table` to find out the maxium length of all string columns. [#14233](https://github.com/ClickHouse/ClickHouse/pull/14233) ([Amos Bird](https://github.com/amosbird)).
* Added an aggregate function `rankCorr` which computes a rank correlation coefficient. [#11769](https://github.com/ClickHouse/ClickHouse/pull/11769) ([antikvist](https://github.com/antikvist)) [#14411](https://github.com/ClickHouse/ClickHouse/pull/14411) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Added table function `view` which turns a subquery into a table object. This helps passing queries around. For instance, it can be used in remote/cluster table functions. [#12567](https://github.com/ClickHouse/ClickHouse/pull/12567) ([Amos Bird](https://github.com/amosbird)).
#### Bug Fix
* Fix bug when `ALTER UPDATE` mutation with Nullable column in assignment expression and constant value (like `UPDATE x = 42`) leads to incorrect value in column or segfault. Fixes [#13634](https://github.com/ClickHouse/ClickHouse/issues/13634), [#14045](https://github.com/ClickHouse/ClickHouse/issues/14045). [#14646](https://github.com/ClickHouse/ClickHouse/pull/14646) ([alesapin](https://github.com/alesapin)).
* Fix wrong Decimal multiplication result caused wrong decimal scale of result column. [#14603](https://github.com/ClickHouse/ClickHouse/pull/14603) ([Artem Zuikov](https://github.com/4ertus2)).
* Fixed the incorrect sorting order of `Nullable` column. This fixes [#14344](https://github.com/ClickHouse/ClickHouse/issues/14344). [#14495](https://github.com/ClickHouse/ClickHouse/pull/14495) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Fixed inconsistent comparison with primary key of type `FixedString` on index analysis if they're compered with a string of less size. This fixes https://github.com/ClickHouse/ClickHouse/issues/14908. [#15033](https://github.com/ClickHouse/ClickHouse/pull/15033) ([Amos Bird](https://github.com/amosbird)).
* Fix bug which leads to wrong merges assignment if table has partitions with a single part. [#14444](https://github.com/ClickHouse/ClickHouse/pull/14444) ([alesapin](https://github.com/alesapin)).
* If function `bar` was called with specifically crafted arguments, buffer overflow was possible. This closes [#13926](https://github.com/ClickHouse/ClickHouse/issues/13926). [#15028](https://github.com/ClickHouse/ClickHouse/pull/15028) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Publish CPU frequencies per logical core in `system.asynchronous_metrics`. This fixes https://github.com/ClickHouse/ClickHouse/issues/14923. [#14924](https://github.com/ClickHouse/ClickHouse/pull/14924) ([Alexander Kuzmenkov](https://github.com/akuzm)).
* Fixed `.metadata.tmp File exists` error when using `MaterializeMySQL` database engine. [#14898](https://github.com/ClickHouse/ClickHouse/pull/14898) ([Winter Zhang](https://github.com/zhang2014)).
* Fix the issue when some invocations of `extractAllGroups` function may trigger "Memory limit exceeded" error. This fixes [#13383](https://github.com/ClickHouse/ClickHouse/issues/13383). [#14889](https://github.com/ClickHouse/ClickHouse/pull/14889) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix SIGSEGV for an attempt to INSERT into StorageFile(fd). [#14887](https://github.com/ClickHouse/ClickHouse/pull/14887) ([Azat Khuzhin](https://github.com/azat)).
* Fix rare error in `SELECT` queries when the queried column has `DEFAULT` expression which depends on the other column which also has `DEFAULT` and not present in select query and not exists on disk. Partially fixes [#14531](https://github.com/ClickHouse/ClickHouse/issues/14531). [#14845](https://github.com/ClickHouse/ClickHouse/pull/14845) ([alesapin](https://github.com/alesapin)).
* Fix wrong monotonicity detection for shrunk `Int -> Int` cast of signed types. It might lead to incorrect query result. This bug is unveiled in [#14513](https://github.com/ClickHouse/ClickHouse/issues/14513). [#14783](https://github.com/ClickHouse/ClickHouse/pull/14783) ([Amos Bird](https://github.com/amosbird)).
* Fixed missed default database name in metadata of materialized view when executing `ALTER ... MODIFY QUERY`. [#14664](https://github.com/ClickHouse/ClickHouse/pull/14664) ([tavplubix](https://github.com/tavplubix)).
* Fix possibly incorrect result of function `has` when LowCardinality and Nullable types are involved. [#14591](https://github.com/ClickHouse/ClickHouse/pull/14591) ([Mike](https://github.com/myrrc)).
* Cleanup data directory after Zookeeper exceptions during CREATE query for tables with ReplicatedMergeTree Engine. [#14563](https://github.com/ClickHouse/ClickHouse/pull/14563) ([Bharat Nallan](https://github.com/bharatnc)).
* Fix rare segfaults in functions with combinator `-Resample`, which could appear in result of overflow with very large parameters. [#14562](https://github.com/ClickHouse/ClickHouse/pull/14562) ([Anton Popov](https://github.com/CurtizJ)).
* Check for array size overflow in `topK` aggregate function. Without this check the user may send a query with carefully crafted parameters that will lead to server crash. This closes [#14452](https://github.com/ClickHouse/ClickHouse/issues/14452). [#14467](https://github.com/ClickHouse/ClickHouse/pull/14467) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Proxy restart/start/stop/reload of SysVinit to systemd (if it is used). [#14460](https://github.com/ClickHouse/ClickHouse/pull/14460) ([Azat Khuzhin](https://github.com/azat)).
* Stop query execution if exception happened in `PipelineExecutor` itself. This could prevent rare possible query hung. [#14334](https://github.com/ClickHouse/ClickHouse/pull/14334) [#14402](https://github.com/ClickHouse/ClickHouse/pull/14402) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix crash during `ALTER` query for table which was created `AS table_function`. Fixes [#14212](https://github.com/ClickHouse/ClickHouse/issues/14212). [#14326](https://github.com/ClickHouse/ClickHouse/pull/14326) ([alesapin](https://github.com/alesapin)).
* Fix exception during ALTER LIVE VIEW query with REFRESH command. LIVE VIEW is an experimental feature. [#14320](https://github.com/ClickHouse/ClickHouse/pull/14320) ([Bharat Nallan](https://github.com/bharatnc)).
* Fix QueryPlan lifetime (for EXPLAIN PIPELINE graph=1) for queries with nested interpreter. [#14315](https://github.com/ClickHouse/ClickHouse/pull/14315) ([Azat Khuzhin](https://github.com/azat)).
* Better check for tuple size in SSD cache complex key external dictionaries. This fixes [#13981](https://github.com/ClickHouse/ClickHouse/issues/13981). [#14313](https://github.com/ClickHouse/ClickHouse/pull/14313) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Disallows `CODEC` on `ALIAS` column type. Fixes [#13911](https://github.com/ClickHouse/ClickHouse/issues/13911). [#14263](https://github.com/ClickHouse/ClickHouse/pull/14263) ([Bharat Nallan](https://github.com/bharatnc)).
* Fix GRANT ALL statement when executed on a non-global level. [#13987](https://github.com/ClickHouse/ClickHouse/pull/13987) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix arrayJoin() capturing in lambda (exception with logical error message was thrown). [#13792](https://github.com/ClickHouse/ClickHouse/pull/13792) ([Azat Khuzhin](https://github.com/azat)).
#### Experimental Feature
* Added `db-generator` tool for random database generation by given SELECT queries. It may faciliate reproducing issues when there is only incomplete bug report from the user. [#14442](https://github.com/ClickHouse/ClickHouse/pull/14442) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)) [#10973](https://github.com/ClickHouse/ClickHouse/issues/10973) ([ZeDRoman](https://github.com/ZeDRoman)).
#### Improvement
* Allow using multi-volume storage configuration in storage Distributed. [#14839](https://github.com/ClickHouse/ClickHouse/pull/14839) ([Pavel Kovalenko](https://github.com/Jokser)).
* Disallow empty time_zone argument in `toStartOf*` type of functions. [#14509](https://github.com/ClickHouse/ClickHouse/pull/14509) ([Bharat Nallan](https://github.com/bharatnc)).
* MySQL handler returns `OK` for queries like `SET @@var = value`. Such statement is ignored. It is needed because some MySQL drivers send `SET @@` query for setup after handshake https://github.com/ClickHouse/ClickHouse/issues/9336#issuecomment-686222422 . [#14469](https://github.com/ClickHouse/ClickHouse/pull/14469) ([BohuTANG](https://github.com/BohuTANG)).
* Now TTLs will be applied during merge if they were not previously materialized. [#14438](https://github.com/ClickHouse/ClickHouse/pull/14438) ([alesapin](https://github.com/alesapin)).
* Now `clickhouse-obfuscator` supports UUID type as proposed in [#13163](https://github.com/ClickHouse/ClickHouse/issues/13163). [#14409](https://github.com/ClickHouse/ClickHouse/pull/14409) ([dimarub2000](https://github.com/dimarub2000)).
* Added new setting `system_events_show_zero_values` as proposed in [#11384](https://github.com/ClickHouse/ClickHouse/issues/11384). [#14404](https://github.com/ClickHouse/ClickHouse/pull/14404) ([dimarub2000](https://github.com/dimarub2000)).
* Implicitly convert primary key to not null in `MaterializeMySQL` (Same as `MySQL`). Fixes [#14114](https://github.com/ClickHouse/ClickHouse/issues/14114). [#14397](https://github.com/ClickHouse/ClickHouse/pull/14397) ([Winter Zhang](https://github.com/zhang2014)).
* Replace wide integers (256 bit) from boost multiprecision with implementation from https://github.com/cerevra/int. 256bit integers are experimental. [#14229](https://github.com/ClickHouse/ClickHouse/pull/14229) ([Artem Zuikov](https://github.com/4ertus2)).
* Add default compression codec for parts in `system.part_log` with the name `default_compression_codec`. [#14116](https://github.com/ClickHouse/ClickHouse/pull/14116) ([alesapin](https://github.com/alesapin)).
* Add precision argument for `DateTime` type. It allows to use `DateTime` name instead of `DateTime64`. [#13761](https://github.com/ClickHouse/ClickHouse/pull/13761) ([Winter Zhang](https://github.com/zhang2014)).
* Added requirepass authorization for `Redis` external dictionary. [#13688](https://github.com/ClickHouse/ClickHouse/pull/13688) ([Ivan Torgashov](https://github.com/it1804)).
* Improvements in `RabbitMQ` engine: added connection and channels failure handling, proper commits, insert failures handling, better exchanges, queue durability and queue resume opportunity, new queue settings. Fixed tests. [#12761](https://github.com/ClickHouse/ClickHouse/pull/12761) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Support custom codecs in compact parts. [#12183](https://github.com/ClickHouse/ClickHouse/pull/12183) ([Anton Popov](https://github.com/CurtizJ)).
#### Performance Improvement
* Optimize queries with LIMIT/LIMIT BY/ORDER BY for distributed with GROUP BY sharding_key (under optimize_skip_unused_shards and optimize_distributed_group_by_sharding_key). [#10373](https://github.com/ClickHouse/ClickHouse/pull/10373) ([Azat Khuzhin](https://github.com/azat)).
* Creating sets for multiple `JOIN` and `IN` in parallel. It may slightly improve performance for queries with several different `IN subquery` expressions. [#14412](https://github.com/ClickHouse/ClickHouse/pull/14412) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Improve Kafka engine performance by providing independent thread for each consumer. Separate thread pool for streaming engines (like Kafka). [#13939](https://github.com/ClickHouse/ClickHouse/pull/13939) ([fastio](https://github.com/fastio)).
#### Build/Testing/Packaging Improvement
* Lower binary size in debug build by removing debug info from `Functions`. This is needed only for one internal project in Yandex who is using very old linker. [#14549](https://github.com/ClickHouse/ClickHouse/pull/14549) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Prepare for build with clang 11. [#14455](https://github.com/ClickHouse/ClickHouse/pull/14455) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix the logic in backport script. In previous versions it was triggered for any labels of 100% red color. It was strange. [#14433](https://github.com/ClickHouse/ClickHouse/pull/14433) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Integration tests use default base config. All config changes are explicit with main_configs, user_configs and dictionaries parameters for instance. [#13647](https://github.com/ClickHouse/ClickHouse/pull/13647) ([Ilya Yatsishin](https://github.com/qoega)).
## ClickHouse release 20.8
### ClickHouse release v20.8.6.6-lts, 2020-11-13
#### Bug Fix
* Fix rare silent crashes when query profiler is on and ClickHouse is installed on OS with glibc version that has (supposedly) broken asynchronous unwind tables for some functions. This fixes [#15301](https://github.com/ClickHouse/ClickHouse/issues/15301). This fixes [#13098](https://github.com/ClickHouse/ClickHouse/issues/13098). [#16846](https://github.com/ClickHouse/ClickHouse/pull/16846) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Now when parsing AVRO from input the LowCardinality is removed from type. Fixes [#16188](https://github.com/ClickHouse/ClickHouse/issues/16188). [#16521](https://github.com/ClickHouse/ClickHouse/pull/16521) ([Mike](https://github.com/myrrc)).
* Fix rapid growth of metadata when using MySQL Master -> MySQL Slave -> ClickHouse MaterializeMySQL Engine, and `slave_parallel_worker` enabled on MySQL Slave, by properly shrinking GTID sets. This fixes [#15951](https://github.com/ClickHouse/ClickHouse/issues/15951). [#16504](https://github.com/ClickHouse/ClickHouse/pull/16504) ([TCeason](https://github.com/TCeason)).
* Fix DROP TABLE for Distributed (racy with INSERT). [#16409](https://github.com/ClickHouse/ClickHouse/pull/16409) ([Azat Khuzhin](https://github.com/azat)).
* Fix processing of very large entries in replication queue. Very large entries may appear in ALTER queries if table structure is extremely large (near 1 MB). This fixes [#16307](https://github.com/ClickHouse/ClickHouse/issues/16307). [#16332](https://github.com/ClickHouse/ClickHouse/pull/16332) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fixed the inconsistent behaviour when a part of return data could be dropped because the set for its filtration wasn't created. [#16308](https://github.com/ClickHouse/ClickHouse/pull/16308) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Fix bug with MySQL database. When MySQL server used as database engine is down some queries raise Exception, because they try to get tables from disabled server, while it's unnecessary. For example, query `SELECT ... FROM system.parts` should work only with MergeTree tables and don't touch MySQL database at all. [#16032](https://github.com/ClickHouse/ClickHouse/pull/16032) ([Kruglov Pavel](https://github.com/Avogar)).
### ClickHouse release v20.8.5.45-lts, 2020-10-29
#### Bug Fix
* Fix double free in case of exception in function `dictGet`. It could have happened if dictionary was loaded with error. [#16429](https://github.com/ClickHouse/ClickHouse/pull/16429) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix group by with totals/rollup/cube modifers and min/max functions over group by keys. Fixes [#16393](https://github.com/ClickHouse/ClickHouse/issues/16393). [#16397](https://github.com/ClickHouse/ClickHouse/pull/16397) ([Anton Popov](https://github.com/CurtizJ)).
* Fix async Distributed INSERT w/ prefer_localhost_replica=0 and internal_replication. [#16358](https://github.com/ClickHouse/ClickHouse/pull/16358) ([Azat Khuzhin](https://github.com/azat)).
* Fix a possible memory leak during `GROUP BY` with string keys, caused by an error in `TwoLevelStringHashTable` implementation. [#16264](https://github.com/ClickHouse/ClickHouse/pull/16264) ([Amos Bird](https://github.com/amosbird)).
* Fix the case when memory can be overallocated regardless to the limit. This closes [#14560](https://github.com/ClickHouse/ClickHouse/issues/14560). [#16206](https://github.com/ClickHouse/ClickHouse/pull/16206) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix `ALTER MODIFY ... ORDER BY` query hang for `ReplicatedVersionedCollapsingMergeTree`. This fixes [#15980](https://github.com/ClickHouse/ClickHouse/issues/15980). [#16011](https://github.com/ClickHouse/ClickHouse/pull/16011) ([alesapin](https://github.com/alesapin)).
* Fix collate name & charset name parser and support `length = 0` for string type. [#16008](https://github.com/ClickHouse/ClickHouse/pull/16008) ([Winter Zhang](https://github.com/zhang2014)).
* Allow to use direct layout for dictionaries with complex keys. [#16007](https://github.com/ClickHouse/ClickHouse/pull/16007) ([Anton Popov](https://github.com/CurtizJ)).
* Prevent replica hang for 5-10 mins when replication error happens after a period of inactivity. [#15987](https://github.com/ClickHouse/ClickHouse/pull/15987) ([filimonov](https://github.com/filimonov)).
* Fix rare segfaults when inserting into or selecting from MaterializedView and concurrently dropping target table (for Atomic database engine). [#15984](https://github.com/ClickHouse/ClickHouse/pull/15984) ([tavplubix](https://github.com/tavplubix)).
* Fix ambiguity in parsing of settings profiles: `CREATE USER ... SETTINGS profile readonly` is now considered as using a profile named `readonly`, not a setting named `profile` with the readonly constraint. This fixes [#15628](https://github.com/ClickHouse/ClickHouse/issues/15628). [#15982](https://github.com/ClickHouse/ClickHouse/pull/15982) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix a crash when database creation fails. [#15954](https://github.com/ClickHouse/ClickHouse/pull/15954) ([Winter Zhang](https://github.com/zhang2014)).
* Fixed `DROP TABLE IF EXISTS` failure with `Table ... doesn't exist` error when table is concurrently renamed (for Atomic database engine). Fixed rare deadlock when concurrently executing some DDL queries with multiple tables (like `DROP DATABASE` and `RENAME TABLE`) Fixed `DROP/DETACH DATABASE` failure with `Table ... doesn't exist` when concurrently executing `DROP/DETACH TABLE`. [#15934](https://github.com/ClickHouse/ClickHouse/pull/15934) ([tavplubix](https://github.com/tavplubix)).
* Fix incorrect empty result for query from `Distributed` table if query has `WHERE`, `PREWHERE` and `GLOBAL IN`. Fixes [#15792](https://github.com/ClickHouse/ClickHouse/issues/15792). [#15933](https://github.com/ClickHouse/ClickHouse/pull/15933) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix possible deadlocks in RBAC. [#15875](https://github.com/ClickHouse/ClickHouse/pull/15875) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix exception `Block structure mismatch` in `SELECT ... ORDER BY DESC` queries which were executed after `ALTER MODIFY COLUMN` query. Fixes [#15800](https://github.com/ClickHouse/ClickHouse/issues/15800). [#15852](https://github.com/ClickHouse/ClickHouse/pull/15852) ([alesapin](https://github.com/alesapin)).
* Fix some cases of queries, in which only virtual columns are selected. Previously `Not found column _nothing in block` exception may be thrown. Fixes [#12298](https://github.com/ClickHouse/ClickHouse/issues/12298). [#15756](https://github.com/ClickHouse/ClickHouse/pull/15756) ([Anton Popov](https://github.com/CurtizJ)).
* Fix error `Cannot find column` which may happen at insertion into `MATERIALIZED VIEW` in case if query for `MV` containes `ARRAY JOIN`. [#15717](https://github.com/ClickHouse/ClickHouse/pull/15717) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fixed too low default value of `max_replicated_logs_to_keep` setting, which might cause replicas to become lost too often. Improve lost replica recovery process by choosing the most up-to-date replica to clone. Also do not remove old parts from lost replica, detach them instead. [#15701](https://github.com/ClickHouse/ClickHouse/pull/15701) ([tavplubix](https://github.com/tavplubix)).
* Fix error `Cannot add simple transform to empty Pipe` which happened while reading from `Buffer` table which has different structure than destination table. It was possible if destination table returned empty result for query. Fixes [#15529](https://github.com/ClickHouse/ClickHouse/issues/15529). [#15662](https://github.com/ClickHouse/ClickHouse/pull/15662) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fixed bug with globs in S3 table function, region from URL was not applied to S3 client configuration. [#15646](https://github.com/ClickHouse/ClickHouse/pull/15646) ([Vladimir Chebotarev](https://github.com/excitoon)).
* Decrement the `ReadonlyReplica` metric when detaching read-only tables. This fixes [#15598](https://github.com/ClickHouse/ClickHouse/issues/15598). [#15592](https://github.com/ClickHouse/ClickHouse/pull/15592) ([sundyli](https://github.com/sundy-li)).
* Throw an error when a single parameter is passed to ReplicatedMergeTree instead of ignoring it. [#15516](https://github.com/ClickHouse/ClickHouse/pull/15516) ([nvartolomei](https://github.com/nvartolomei)).
#### Improvement
* Now it's allowed to execute `ALTER ... ON CLUSTER` queries regardless of the `<internal_replication>` setting in cluster config. [#16075](https://github.com/ClickHouse/ClickHouse/pull/16075) ([alesapin](https://github.com/alesapin)).
* Unfold `{database}`, `{table}` and `{uuid}` macros in `ReplicatedMergeTree` arguments on table creation. [#16159](https://github.com/ClickHouse/ClickHouse/pull/16159) ([tavplubix](https://github.com/tavplubix)).
### ClickHouse release v20.8.4.11-lts, 2020-10-09
#### Bug Fix
* Fix the order of destruction for resources in `ReadFromStorage` step of query plan. It might cause crashes in rare cases. Possibly connected with [#15610](https://github.com/ClickHouse/ClickHouse/issues/15610). [#15645](https://github.com/ClickHouse/ClickHouse/pull/15645) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fixed `Element ... is not a constant expression` error when using `JSON*` function result in `VALUES`, `LIMIT` or right side of `IN` operator. [#15589](https://github.com/ClickHouse/ClickHouse/pull/15589) ([tavplubix](https://github.com/tavplubix)).
* Prevent the possibility of error message `Could not calculate available disk space (statvfs), errno: 4, strerror: Interrupted system call`. This fixes [#15541](https://github.com/ClickHouse/ClickHouse/issues/15541). [#15557](https://github.com/ClickHouse/ClickHouse/pull/15557) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Significantly reduce memory usage in AggregatingInOrderTransform/optimize_aggregation_in_order. [#15543](https://github.com/ClickHouse/ClickHouse/pull/15543) ([Azat Khuzhin](https://github.com/azat)).
* Mutation might hang waiting for some non-existent part after `MOVE` or `REPLACE PARTITION` or, in rare cases, after `DETACH` or `DROP PARTITION`. It's fixed. [#15537](https://github.com/ClickHouse/ClickHouse/pull/15537) ([tavplubix](https://github.com/tavplubix)).
* Fix bug when `ILIKE` operator stops being case insensitive if `LIKE` with the same pattern was executed. [#15536](https://github.com/ClickHouse/ClickHouse/pull/15536) ([alesapin](https://github.com/alesapin)).
* Fix `Missing columns` errors when selecting columns which absent in data, but depend on other columns which also absent in data. Fixes [#15530](https://github.com/ClickHouse/ClickHouse/issues/15530). [#15532](https://github.com/ClickHouse/ClickHouse/pull/15532) ([alesapin](https://github.com/alesapin)).
* Fix bug with event subscription in DDLWorker which rarely may lead to query hangs in `ON CLUSTER`. Introduced in [#13450](https://github.com/ClickHouse/ClickHouse/issues/13450). [#15477](https://github.com/ClickHouse/ClickHouse/pull/15477) ([alesapin](https://github.com/alesapin)).
* Report proper error when the second argument of `boundingRatio` aggregate function has a wrong type. [#15407](https://github.com/ClickHouse/ClickHouse/pull/15407) ([detailyang](https://github.com/detailyang)).
* Fix race condition during MergeTree table rename and background cleanup. [#15304](https://github.com/ClickHouse/ClickHouse/pull/15304) ([alesapin](https://github.com/alesapin)).
* Fix rare race condition on server startup when system.logs are enabled. [#15300](https://github.com/ClickHouse/ClickHouse/pull/15300) ([alesapin](https://github.com/alesapin)).
* Fix MSan report in QueryLog. Uninitialized memory can be used for the field `memory_usage`. [#15258](https://github.com/ClickHouse/ClickHouse/pull/15258) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix instance crash when using joinGet with LowCardinality types. This fixes https://github.com/ClickHouse/ClickHouse/issues/15214. [#15220](https://github.com/ClickHouse/ClickHouse/pull/15220) ([Amos Bird](https://github.com/amosbird)).
* Fix bug in table engine `Buffer` which doesn't allow to insert data of new structure into `Buffer` after `ALTER` query. Fixes [#15117](https://github.com/ClickHouse/ClickHouse/issues/15117). [#15192](https://github.com/ClickHouse/ClickHouse/pull/15192) ([alesapin](https://github.com/alesapin)).
* Adjust decimals field size in mysql column definition packet. [#15152](https://github.com/ClickHouse/ClickHouse/pull/15152) ([maqroll](https://github.com/maqroll)).
* We already use padded comparison between String and FixedString (https://github.com/ClickHouse/ClickHouse/blob/master/src/Functions/FunctionsComparison.h#L333). This PR applies the same logic to field comparison which corrects the usage of FixedString as primary keys. This fixes https://github.com/ClickHouse/ClickHouse/issues/14908. [#15033](https://github.com/ClickHouse/ClickHouse/pull/15033) ([Amos Bird](https://github.com/amosbird)).
* If function `bar` was called with specifically crafter arguments, buffer overflow was possible. This closes [#13926](https://github.com/ClickHouse/ClickHouse/issues/13926). [#15028](https://github.com/ClickHouse/ClickHouse/pull/15028) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fixed `Cannot rename ... errno: 22, strerror: Invalid argument` error on DDL query execution in Atomic database when running clickhouse-server in docker on Mac OS. [#15024](https://github.com/ClickHouse/ClickHouse/pull/15024) ([tavplubix](https://github.com/tavplubix)).
* Now settings `number_of_free_entries_in_pool_to_execute_mutation` and `number_of_free_entries_in_pool_to_lower_max_size_of_merge` can be equal to `background_pool_size`. [#14975](https://github.com/ClickHouse/ClickHouse/pull/14975) ([alesapin](https://github.com/alesapin)).
* Fix to make predicate push down work when subquery contains finalizeAggregation function. Fixes [#14847](https://github.com/ClickHouse/ClickHouse/issues/14847). [#14937](https://github.com/ClickHouse/ClickHouse/pull/14937) ([filimonov](https://github.com/filimonov)).
* Publish CPU frequencies per logical core in `system.asynchronous_metrics`. This fixes https://github.com/ClickHouse/ClickHouse/issues/14923. [#14924](https://github.com/ClickHouse/ClickHouse/pull/14924) ([Alexander Kuzmenkov](https://github.com/akuzm)).
* Fixed `.metadata.tmp File exists` error when using `MaterializeMySQL` database engine. [#14898](https://github.com/ClickHouse/ClickHouse/pull/14898) ([Winter Zhang](https://github.com/zhang2014)).
* Fix a problem where the server may get stuck on startup while talking to ZooKeeper, if the configuration files have to be fetched from ZK (using the `from_zk` include option). This fixes [#14814](https://github.com/ClickHouse/ClickHouse/issues/14814). [#14843](https://github.com/ClickHouse/ClickHouse/pull/14843) ([Alexander Kuzmenkov](https://github.com/akuzm)).
* Fix wrong monotonicity detection for shrunk `Int -> Int` cast of signed types. It might lead to incorrect query result. This bug is unveiled in [#14513](https://github.com/ClickHouse/ClickHouse/issues/14513). [#14783](https://github.com/ClickHouse/ClickHouse/pull/14783) ([Amos Bird](https://github.com/amosbird)).
* Fixed the incorrect sorting order of `Nullable` column. This fixes [#14344](https://github.com/ClickHouse/ClickHouse/issues/14344). [#14495](https://github.com/ClickHouse/ClickHouse/pull/14495) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
#### Improvement
* Now it's possible to change the type of version column for `VersionedCollapsingMergeTree` with `ALTER` query. [#15442](https://github.com/ClickHouse/ClickHouse/pull/15442) ([alesapin](https://github.com/alesapin)).
### ClickHouse release v20.8.3.18-stable, 2020-09-18
#### Bug Fix
* Fix the issue when some invocations of `extractAllGroups` function may trigger "Memory limit exceeded" error. This fixes [#13383](https://github.com/ClickHouse/ClickHouse/issues/13383). [#14889](https://github.com/ClickHouse/ClickHouse/pull/14889) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix SIGSEGV for an attempt to INSERT into StorageFile(fd). [#14887](https://github.com/ClickHouse/ClickHouse/pull/14887) ([Azat Khuzhin](https://github.com/azat)).
* Fix rare error in `SELECT` queries when the queried column has `DEFAULT` expression which depends on the other column which also has `DEFAULT` and not present in select query and not exists on disk. Partially fixes [#14531](https://github.com/ClickHouse/ClickHouse/issues/14531). [#14845](https://github.com/ClickHouse/ClickHouse/pull/14845) ([alesapin](https://github.com/alesapin)).
* Fixed missed default database name in metadata of materialized view when executing `ALTER ... MODIFY QUERY`. [#14664](https://github.com/ClickHouse/ClickHouse/pull/14664) ([tavplubix](https://github.com/tavplubix)).
* Fix bug when `ALTER UPDATE` mutation with Nullable column in assignment expression and constant value (like `UPDATE x = 42`) leads to incorrect value in column or segfault. Fixes [#13634](https://github.com/ClickHouse/ClickHouse/issues/13634), [#14045](https://github.com/ClickHouse/ClickHouse/issues/14045). [#14646](https://github.com/ClickHouse/ClickHouse/pull/14646) ([alesapin](https://github.com/alesapin)).
* Fix wrong Decimal multiplication result caused wrong decimal scale of result column. [#14603](https://github.com/ClickHouse/ClickHouse/pull/14603) ([Artem Zuikov](https://github.com/4ertus2)).
* Added the checker as neither calling `lc->isNullable()` nor calling `ls->getDictionaryPtr()->isNullable()` would return the correct result. [#14591](https://github.com/ClickHouse/ClickHouse/pull/14591) ([myrrc](https://github.com/myrrc)).
* Cleanup data directory after Zookeeper exceptions during CreateQuery for StorageReplicatedMergeTree Engine. [#14563](https://github.com/ClickHouse/ClickHouse/pull/14563) ([Bharat Nallan](https://github.com/bharatnc)).
* Fix rare segfaults in functions with combinator -Resample, which could appear in result of overflow with very large parameters. [#14562](https://github.com/ClickHouse/ClickHouse/pull/14562) ([Anton Popov](https://github.com/CurtizJ)).
#### Improvement
* Speed up server shutdown process if there are ongoing S3 requests. [#14858](https://github.com/ClickHouse/ClickHouse/pull/14858) ([Pavel Kovalenko](https://github.com/Jokser)).
* Allow using multi-volume storage configuration in storage Distributed. [#14839](https://github.com/ClickHouse/ClickHouse/pull/14839) ([Pavel Kovalenko](https://github.com/Jokser)).
* Speed up server shutdown process if there are ongoing S3 requests. [#14496](https://github.com/ClickHouse/ClickHouse/pull/14496) ([Pavel Kovalenko](https://github.com/Jokser)).
* Support custom codecs in compact parts. [#12183](https://github.com/ClickHouse/ClickHouse/pull/12183) ([Anton Popov](https://github.com/CurtizJ)).
### ClickHouse release v20.8.2.3-stable, 2020-09-08
#### Backward Incompatible Change
* Now `OPTIMIZE FINAL` query doesn't recalculate TTL for parts that were added before TTL was created. Use `ALTER TABLE ... MATERIALIZE TTL` once to calculate them, after that `OPTIMIZE FINAL` will evaluate TTL's properly. This behavior never worked for replicated tables. [#14220](https://github.com/ClickHouse/ClickHouse/pull/14220) ([alesapin](https://github.com/alesapin)).
* Extend `parallel_distributed_insert_select` setting, adding an option to run `INSERT` into local table. The setting changes type from `Bool` to `UInt64`, so the values `false` and `true` are no longer supported. If you have these values in server configuration, the server will not start. Please replace them with `0` and `1`, respectively. [#14060](https://github.com/ClickHouse/ClickHouse/pull/14060) ([Azat Khuzhin](https://github.com/azat)).
* Remove support for the `ODBCDriver` input/output format. This was a deprecated format once used for communication with the ClickHouse ODBC driver, now long superseded by the `ODBCDriver2` format. Resolves [#13629](https://github.com/ClickHouse/ClickHouse/issues/13629). [#13847](https://github.com/ClickHouse/ClickHouse/pull/13847) ([hexiaoting](https://github.com/hexiaoting)).
#### New Feature
* Add the ability to specify `Default` compression codec for columns that correspond to settings specified in `config.xml`. Implements: [#9074](https://github.com/ClickHouse/ClickHouse/issues/9074). [#14049](https://github.com/ClickHouse/ClickHouse/pull/14049) ([alesapin](https://github.com/alesapin)).
* Support Kerberos authentication in Kafka, using `krb5` and `cyrus-sasl` libraries. [#12771](https://github.com/ClickHouse/ClickHouse/pull/12771) ([Ilya Golshtein](https://github.com/ilejn)).
* Add function `normalizeQuery` that replaces literals, sequences of literals and complex aliases with placeholders. Add function `normalizedQueryHash` that returns identical 64bit hash values for similar queries. It helps to analyze query log. This closes [#11271](https://github.com/ClickHouse/ClickHouse/issues/11271). [#13816](https://github.com/ClickHouse/ClickHouse/pull/13816) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add `time_zones` table. [#13880](https://github.com/ClickHouse/ClickHouse/pull/13880) ([Bharat Nallan](https://github.com/bharatnc)).
* Add function `defaultValueOfTypeName` that returns the default value for a given type. [#13877](https://github.com/ClickHouse/ClickHouse/pull/13877) ([hcz](https://github.com/hczhcz)).
* Add `countDigits(x)` function that count number of decimal digits in integer or decimal column. Add `isDecimalOverflow(d, [p])` function that checks if the value in Decimal column is out of its (or specified) precision. [#14151](https://github.com/ClickHouse/ClickHouse/pull/14151) ([Artem Zuikov](https://github.com/4ertus2)).
* Add `quantileExactLow` and `quantileExactHigh` implementations with respective aliases for `medianExactLow` and `medianExactHigh`. [#13818](https://github.com/ClickHouse/ClickHouse/pull/13818) ([Bharat Nallan](https://github.com/bharatnc)).
* Added `date_trunc` function that truncates a date/time value to a specified date/time part. [#13888](https://github.com/ClickHouse/ClickHouse/pull/13888) ([Vladimir Golovchenko](https://github.com/vladimir-golovchenko)).
* Add new optional section `<user_directories>` to the main config. [#13425](https://github.com/ClickHouse/ClickHouse/pull/13425) ([Vitaly Baranov](https://github.com/vitlibar)).
* Add `ALTER SAMPLE BY` statement that allows to change table sample clause. [#13280](https://github.com/ClickHouse/ClickHouse/pull/13280) ([Amos Bird](https://github.com/amosbird)).
* Function `position` now supports optional `start_pos` argument. [#13237](https://github.com/ClickHouse/ClickHouse/pull/13237) ([vdimir](https://github.com/vdimir)).
#### Bug Fix
* Fix visible data clobbering by progress bar in client in interactive mode. This fixes [#12562](https://github.com/ClickHouse/ClickHouse/issues/12562) and [#13369](https://github.com/ClickHouse/ClickHouse/issues/13369) and [#13584](https://github.com/ClickHouse/ClickHouse/issues/13584) and fixes [#12964](https://github.com/ClickHouse/ClickHouse/issues/12964). [#13691](https://github.com/ClickHouse/ClickHouse/pull/13691) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fixed incorrect sorting order if `LowCardinality` column when sorting by multiple columns. This fixes [#13958](https://github.com/ClickHouse/ClickHouse/issues/13958). [#14223](https://github.com/ClickHouse/ClickHouse/pull/14223) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Check for array size overflow in `topK` aggregate function. Without this check the user may send a query with carefully crafter parameters that will lead to server crash. This closes [#14452](https://github.com/ClickHouse/ClickHouse/issues/14452). [#14467](https://github.com/ClickHouse/ClickHouse/pull/14467) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix bug which can lead to wrong merges assignment if table has partitions with a single part. [#14444](https://github.com/ClickHouse/ClickHouse/pull/14444) ([alesapin](https://github.com/alesapin)).
* Stop query execution if exception happened in `PipelineExecutor` itself. This could prevent rare possible query hung. Continuation of [#14334](https://github.com/ClickHouse/ClickHouse/issues/14334). [#14402](https://github.com/ClickHouse/ClickHouse/pull/14402) [#14334](https://github.com/ClickHouse/ClickHouse/pull/14334) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix crash during `ALTER` query for table which was created `AS table_function`. Fixes [#14212](https://github.com/ClickHouse/ClickHouse/issues/14212). [#14326](https://github.com/ClickHouse/ClickHouse/pull/14326) ([alesapin](https://github.com/alesapin)).
* Fix exception during ALTER LIVE VIEW query with REFRESH command. Live view is an experimental feature. [#14320](https://github.com/ClickHouse/ClickHouse/pull/14320) ([Bharat Nallan](https://github.com/bharatnc)).
* Fix QueryPlan lifetime (for EXPLAIN PIPELINE graph=1) for queries with nested interpreter. [#14315](https://github.com/ClickHouse/ClickHouse/pull/14315) ([Azat Khuzhin](https://github.com/azat)).
* Fix segfault in `clickhouse-odbc-bridge` during schema fetch from some external sources. This PR fixes https://github.com/ClickHouse/ClickHouse/issues/13861. [#14267](https://github.com/ClickHouse/ClickHouse/pull/14267) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix crash in mark inclusion search introduced in https://github.com/ClickHouse/ClickHouse/pull/12277. [#14225](https://github.com/ClickHouse/ClickHouse/pull/14225) ([Amos Bird](https://github.com/amosbird)).
* Fix creation of tables with named tuples. This fixes [#13027](https://github.com/ClickHouse/ClickHouse/issues/13027). [#14143](https://github.com/ClickHouse/ClickHouse/pull/14143) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix formatting of minimal negative decimal numbers. This fixes https://github.com/ClickHouse/ClickHouse/issues/14111. [#14119](https://github.com/ClickHouse/ClickHouse/pull/14119) ([Alexander Kuzmenkov](https://github.com/akuzm)).
* Fix `DistributedFilesToInsert` metric (zeroed when it should not). [#14095](https://github.com/ClickHouse/ClickHouse/pull/14095) ([Azat Khuzhin](https://github.com/azat)).
* Fix `pointInPolygon` with const 2d array as polygon. [#14079](https://github.com/ClickHouse/ClickHouse/pull/14079) ([Alexey Ilyukhov](https://github.com/livace)).
* Fixed wrong mount point in extra info for `Poco::Exception: no space left on device`. [#14050](https://github.com/ClickHouse/ClickHouse/pull/14050) ([tavplubix](https://github.com/tavplubix)).
* Fix GRANT ALL statement when executed on a non-global level. [#13987](https://github.com/ClickHouse/ClickHouse/pull/13987) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix parser to reject create table as table function with engine. [#13940](https://github.com/ClickHouse/ClickHouse/pull/13940) ([hcz](https://github.com/hczhcz)).
* Fix wrong results in select queries with `DISTINCT` keyword and subqueries with UNION ALL in case `optimize_duplicate_order_by_and_distinct` setting is enabled. [#13925](https://github.com/ClickHouse/ClickHouse/pull/13925) ([Artem Zuikov](https://github.com/4ertus2)).
* Fixed potential deadlock when renaming `Distributed` table. [#13922](https://github.com/ClickHouse/ClickHouse/pull/13922) ([tavplubix](https://github.com/tavplubix)).
* Fix incorrect sorting for `FixedString` columns when sorting by multiple columns. Fixes [#13182](https://github.com/ClickHouse/ClickHouse/issues/13182). [#13887](https://github.com/ClickHouse/ClickHouse/pull/13887) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix potentially imprecise result of `topK`/`topKWeighted` merge (with non-default parameters). [#13817](https://github.com/ClickHouse/ClickHouse/pull/13817) ([Azat Khuzhin](https://github.com/azat)).
* Fix reading from MergeTree table with INDEX of type SET fails when comparing against NULL. This fixes [#13686](https://github.com/ClickHouse/ClickHouse/issues/13686). [#13793](https://github.com/ClickHouse/ClickHouse/pull/13793) ([Amos Bird](https://github.com/amosbird)).
* Fix `arrayJoin` capturing in lambda (LOGICAL_ERROR). [#13792](https://github.com/ClickHouse/ClickHouse/pull/13792) ([Azat Khuzhin](https://github.com/azat)).
* Add step overflow check in function `range`. [#13790](https://github.com/ClickHouse/ClickHouse/pull/13790) ([Azat Khuzhin](https://github.com/azat)).
* Fixed `Directory not empty` error when concurrently executing `DROP DATABASE` and `CREATE TABLE`. [#13756](https://github.com/ClickHouse/ClickHouse/pull/13756) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add range check for `h3KRing` function. This fixes [#13633](https://github.com/ClickHouse/ClickHouse/issues/13633). [#13752](https://github.com/ClickHouse/ClickHouse/pull/13752) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix race condition between DETACH and background merges. Parts may revive after detach. This is continuation of [#8602](https://github.com/ClickHouse/ClickHouse/issues/8602) that did not fix the issue but introduced a test that started to fail in very rare cases, demonstrating the issue. [#13746](https://github.com/ClickHouse/ClickHouse/pull/13746) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix logging Settings.Names/Values when log_queries_min_type > QUERY_START. [#13737](https://github.com/ClickHouse/ClickHouse/pull/13737) ([Azat Khuzhin](https://github.com/azat)).
* Fixes `/replicas_status` endpoint response status code when verbose=1. [#13722](https://github.com/ClickHouse/ClickHouse/pull/13722) ([javi santana](https://github.com/javisantana)).
* Fix incorrect message in `clickhouse-server.init` while checking user and group. [#13711](https://github.com/ClickHouse/ClickHouse/pull/13711) ([ylchou](https://github.com/ylchou)).
* Do not optimize any(arrayJoin()) -> arrayJoin() under `optimize_move_functions_out_of_any` setting. [#13681](https://github.com/ClickHouse/ClickHouse/pull/13681) ([Azat Khuzhin](https://github.com/azat)).
* Fix crash in JOIN with StorageMerge and `set enable_optimize_predicate_expression=1`. [#13679](https://github.com/ClickHouse/ClickHouse/pull/13679) ([Artem Zuikov](https://github.com/4ertus2)).
* Fix typo in error message about `The value of 'number_of_free_entries_in_pool_to_lower_max_size_of_merge' setting`. [#13678](https://github.com/ClickHouse/ClickHouse/pull/13678) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Concurrent `ALTER ... REPLACE/MOVE PARTITION ...` queries might cause deadlock. It's fixed. [#13626](https://github.com/ClickHouse/ClickHouse/pull/13626) ([tavplubix](https://github.com/tavplubix)).
* Fixed the behaviour when sometimes cache-dictionary returned default value instead of present value from source. [#13624](https://github.com/ClickHouse/ClickHouse/pull/13624) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Fix secondary indices corruption in compact parts. Compact parts are experimental feature. [#13538](https://github.com/ClickHouse/ClickHouse/pull/13538) ([Anton Popov](https://github.com/CurtizJ)).
* Fix premature `ON CLUSTER` timeouts for queries that must be executed on a single replica. Fixes [#6704](https://github.com/ClickHouse/ClickHouse/issues/6704), [#7228](https://github.com/ClickHouse/ClickHouse/issues/7228), [#13361](https://github.com/ClickHouse/ClickHouse/issues/13361), [#11884](https://github.com/ClickHouse/ClickHouse/issues/11884). [#13450](https://github.com/ClickHouse/ClickHouse/pull/13450) ([alesapin](https://github.com/alesapin)).
* Fix wrong code in function `netloc`. This fixes [#13335](https://github.com/ClickHouse/ClickHouse/issues/13335). [#13446](https://github.com/ClickHouse/ClickHouse/pull/13446) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix possible race in `StorageMemory`. [#13416](https://github.com/ClickHouse/ClickHouse/pull/13416) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix missing or excessive headers in `TSV/CSVWithNames` formats in HTTP protocol. This fixes [#12504](https://github.com/ClickHouse/ClickHouse/issues/12504). [#13343](https://github.com/ClickHouse/ClickHouse/pull/13343) ([Azat Khuzhin](https://github.com/azat)).
* Fix parsing row policies from users.xml when names of databases or tables contain dots. This fixes https://github.com/ClickHouse/ClickHouse/issues/5779, https://github.com/ClickHouse/ClickHouse/issues/12527. [#13199](https://github.com/ClickHouse/ClickHouse/pull/13199) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix access to `redis` dictionary after connection was dropped once. It may happen with `cache` and `direct` dictionary layouts. [#13082](https://github.com/ClickHouse/ClickHouse/pull/13082) ([Anton Popov](https://github.com/CurtizJ)).
* Removed wrong auth access check when using ClickHouseDictionarySource to query remote tables. [#12756](https://github.com/ClickHouse/ClickHouse/pull/12756) ([sundyli](https://github.com/sundy-li)).
* Properly distinguish subqueries in some cases for common subexpression elimination. https://github.com/ClickHouse/ClickHouse/issues/8333. [#8367](https://github.com/ClickHouse/ClickHouse/pull/8367) ([Amos Bird](https://github.com/amosbird)).
#### Improvement
* Disallows `CODEC` on `ALIAS` column type. Fixes [#13911](https://github.com/ClickHouse/ClickHouse/issues/13911). [#14263](https://github.com/ClickHouse/ClickHouse/pull/14263) ([Bharat Nallan](https://github.com/bharatnc)).
* When waiting for a dictionary update to complete, use the timeout specified by `query_wait_timeout_milliseconds` setting instead of a hard-coded value. [#14105](https://github.com/ClickHouse/ClickHouse/pull/14105) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Add setting `min_index_granularity_bytes` that protects against accidentally creating a table with very low `index_granularity_bytes` setting. [#14139](https://github.com/ClickHouse/ClickHouse/pull/14139) ([Bharat Nallan](https://github.com/bharatnc)).
* Now it's possible to fetch partitions from clusters that use different ZooKeeper: `ALTER TABLE table_name FETCH PARTITION partition_expr FROM 'zk-name:/path-in-zookeeper'`. It's useful for shipping data to new clusters. [#14155](https://github.com/ClickHouse/ClickHouse/pull/14155) ([Amos Bird](https://github.com/amosbird)).
* Slightly better performance of Memory table if it was constructed from a huge number of very small blocks (that's unlikely). Author of the idea: [Mark Papadakis](https://github.com/markpapadakis). Closes [#14043](https://github.com/ClickHouse/ClickHouse/issues/14043). [#14056](https://github.com/ClickHouse/ClickHouse/pull/14056) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Conditional aggregate functions (for example: `avgIf`, `sumIf`, `maxIf`) should return `NULL` when miss rows and use nullable arguments. [#13964](https://github.com/ClickHouse/ClickHouse/pull/13964) ([Winter Zhang](https://github.com/zhang2014)).
* Increase limit in -Resample combinator to 1M. [#13947](https://github.com/ClickHouse/ClickHouse/pull/13947) ([Mikhail f. Shiryaev](https://github.com/Felixoid)).
* Corrected an error in AvroConfluent format that caused the Kafka table engine to stop processing messages when an abnormally small, malformed, message was received. [#13941](https://github.com/ClickHouse/ClickHouse/pull/13941) ([Gervasio Varela](https://github.com/gervarela)).
* Fix wrong error for long queries. It was possible to get syntax error other than `Max query size exceeded` for correct query. [#13928](https://github.com/ClickHouse/ClickHouse/pull/13928) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Better error message for null value of `TabSeparated` format. [#13906](https://github.com/ClickHouse/ClickHouse/pull/13906) ([jiang tao](https://github.com/tomjiang1987)).
* Function `arrayCompact` will compare NaNs bitwise if the type of array elements is Float32/Float64. In previous versions NaNs were always not equal if the type of array elements is Float32/Float64 and were always equal if the type is more complex, like Nullable(Float64). This closes [#13857](https://github.com/ClickHouse/ClickHouse/issues/13857). [#13868](https://github.com/ClickHouse/ClickHouse/pull/13868) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix data race in `lgamma` function. This race was caught only in `tsan`, no side effects a really happened. [#13842](https://github.com/ClickHouse/ClickHouse/pull/13842) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Avoid too slow queries when arrays are manipulated as fields. Throw exception instead. [#13753](https://github.com/ClickHouse/ClickHouse/pull/13753) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Added Redis requirepass authorization (for redis dictionary source). [#13688](https://github.com/ClickHouse/ClickHouse/pull/13688) ([Ivan Torgashov](https://github.com/it1804)).
* Add MergeTree Write-Ahead-Log (WAL) dump tool. WAL is an experimental feature. [#13640](https://github.com/ClickHouse/ClickHouse/pull/13640) ([BohuTANG](https://github.com/BohuTANG)).
* In previous versions `lcm` function may produce assertion violation in debug build if called with specifically crafted arguments. This fixes [#13368](https://github.com/ClickHouse/ClickHouse/issues/13368). [#13510](https://github.com/ClickHouse/ClickHouse/pull/13510) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Provide monotonicity for `toDate/toDateTime` functions in more cases. Monotonicity information is used for index analysis (more complex queries will be able to use index). Now the input arguments are saturated more naturally and provides better monotonicity. [#13497](https://github.com/ClickHouse/ClickHouse/pull/13497) ([Amos Bird](https://github.com/amosbird)).
* Support compound identifiers for custom settings. Custom settings is an integration point of ClickHouse codebase with other codebases (no benefits for ClickHouse itself) [#13496](https://github.com/ClickHouse/ClickHouse/pull/13496) ([Vitaly Baranov](https://github.com/vitlibar)).
* Move parts from DiskLocal to DiskS3 in parallel. `DiskS3` is an experimental feature. [#13459](https://github.com/ClickHouse/ClickHouse/pull/13459) ([Pavel Kovalenko](https://github.com/Jokser)).
* Enable mixed granularity parts by default. [#13449](https://github.com/ClickHouse/ClickHouse/pull/13449) ([alesapin](https://github.com/alesapin)).
* Proper remote host checking in S3 redirects (security-related thing). [#13404](https://github.com/ClickHouse/ClickHouse/pull/13404) ([Vladimir Chebotarev](https://github.com/excitoon)).
* Add `QueryTimeMicroseconds`, `SelectQueryTimeMicroseconds` and `InsertQueryTimeMicroseconds` to system.events. [#13336](https://github.com/ClickHouse/ClickHouse/pull/13336) ([ianton-ru](https://github.com/ianton-ru)).
* Fix debug assertion when Decimal has too large negative exponent. Fixes [#13188](https://github.com/ClickHouse/ClickHouse/issues/13188). [#13228](https://github.com/ClickHouse/ClickHouse/pull/13228) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Added cache layer for DiskS3 (cache to local disk mark and index files). `DiskS3` is an experimental feature. [#13076](https://github.com/ClickHouse/ClickHouse/pull/13076) ([Pavel Kovalenko](https://github.com/Jokser)).
* Fix readline so it dumps history to file now. [#13600](https://github.com/ClickHouse/ClickHouse/pull/13600) ([Amos Bird](https://github.com/amosbird)).
* Create `system` database with `Atomic` engine by default (a preparation to enable `Atomic` database engine by default everywhere). [#13680](https://github.com/ClickHouse/ClickHouse/pull/13680) ([tavplubix](https://github.com/tavplubix)).
#### Performance Improvement
* Slightly optimize very short queries with `LowCardinality`. [#14129](https://github.com/ClickHouse/ClickHouse/pull/14129) ([Anton Popov](https://github.com/CurtizJ)).
* Enable parallel INSERTs for table engines `Null`, `Memory`, `Distributed` and `Buffer` when the setting `max_insert_threads` is set. [#14120](https://github.com/ClickHouse/ClickHouse/pull/14120) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fail fast if `max_rows_to_read` limit is exceeded on parts scan. The motivation behind this change is to skip ranges scan for all selected parts if it is clear that `max_rows_to_read` is already exceeded. The change is quite noticeable for queries over big number of parts. [#13677](https://github.com/ClickHouse/ClickHouse/pull/13677) ([Roman Khavronenko](https://github.com/hagen1778)).
* Slightly improve performance of aggregation by UInt8/UInt16 keys. [#13099](https://github.com/ClickHouse/ClickHouse/pull/13099) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Optimize `has()`, `indexOf()` and `countEqual()` functions for `Array(LowCardinality(T))` and constant right arguments. [#12550](https://github.com/ClickHouse/ClickHouse/pull/12550) ([myrrc](https://github.com/myrrc)).
* When performing trivial `INSERT SELECT` queries, automatically set `max_threads` to 1 or `max_insert_threads`, and set `max_block_size` to `min_insert_block_size_rows`. Related to [#5907](https://github.com/ClickHouse/ClickHouse/issues/5907). [#12195](https://github.com/ClickHouse/ClickHouse/pull/12195) ([flynn](https://github.com/ucasFL)).
#### Experimental Feature
* ClickHouse can work as MySQL replica - it is implemented by `MaterializeMySQL` database engine. Implements [#4006](https://github.com/ClickHouse/ClickHouse/issues/4006). [#10851](https://github.com/ClickHouse/ClickHouse/pull/10851) ([Winter Zhang](https://github.com/zhang2014)).
* Add types `Int128`, `Int256`, `UInt256` and related functions for them. Extend Decimals with Decimal256 (precision up to 76 digits). New types are under the setting `allow_experimental_bigint_types`. It is working extremely slow and bad. The implementation is incomplete. Please don't use this feature. [#13097](https://github.com/ClickHouse/ClickHouse/pull/13097) ([Artem Zuikov](https://github.com/4ertus2)).
#### Build/Testing/Packaging Improvement
* Added `clickhouse install` script, that is useful if you only have a single binary. [#13528](https://github.com/ClickHouse/ClickHouse/pull/13528) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Allow to run `clickhouse` binary without configuration. [#13515](https://github.com/ClickHouse/ClickHouse/pull/13515) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Enable check for typos in code with `codespell`. [#13513](https://github.com/ClickHouse/ClickHouse/pull/13513) [#13511](https://github.com/ClickHouse/ClickHouse/pull/13511) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Enable Shellcheck in CI as a linter of .sh tests. This closes [#13168](https://github.com/ClickHouse/ClickHouse/issues/13168). [#13530](https://github.com/ClickHouse/ClickHouse/pull/13530) [#13529](https://github.com/ClickHouse/ClickHouse/pull/13529) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add a CMake option to fail configuration instead of auto-reconfiguration, enabled by default. [#13687](https://github.com/ClickHouse/ClickHouse/pull/13687) ([Konstantin](https://github.com/podshumok)).
* Expose version of embedded tzdata via TZDATA_VERSION in system.build_options. [#13648](https://github.com/ClickHouse/ClickHouse/pull/13648) ([filimonov](https://github.com/filimonov)).
* Improve generation of system.time_zones table during build. Closes [#14209](https://github.com/ClickHouse/ClickHouse/issues/14209). [#14215](https://github.com/ClickHouse/ClickHouse/pull/14215) ([filimonov](https://github.com/filimonov)).
* Build ClickHouse with the most fresh tzdata from package repository. [#13623](https://github.com/ClickHouse/ClickHouse/pull/13623) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add the ability to write js-style comments in skip_list.json. [#14159](https://github.com/ClickHouse/ClickHouse/pull/14159) ([alesapin](https://github.com/alesapin)).
* Ensure that there is no copy-pasted GPL code. [#13514](https://github.com/ClickHouse/ClickHouse/pull/13514) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Switch tests docker images to use test-base parent. [#14167](https://github.com/ClickHouse/ClickHouse/pull/14167) ([Ilya Yatsishin](https://github.com/qoega)).
* Adding retry logic when bringing up docker-compose cluster; Increasing COMPOSE_HTTP_TIMEOUT. [#14112](https://github.com/ClickHouse/ClickHouse/pull/14112) ([vzakaznikov](https://github.com/vzakaznikov)).
* Enabled `system.text_log` in stress test to find more bugs. [#13855](https://github.com/ClickHouse/ClickHouse/pull/13855) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Testflows LDAP module: adding missing certificates and dhparam.pem for openldap4. [#13780](https://github.com/ClickHouse/ClickHouse/pull/13780) ([vzakaznikov](https://github.com/vzakaznikov)).
* ZooKeeper cannot work reliably in unit tests in CI infrastructure. Using unit tests for ZooKeeper interaction with real ZooKeeper is bad idea from the start (unit tests are not supposed to verify complex distributed systems). We already using integration tests for this purpose and they are better suited. [#13745](https://github.com/ClickHouse/ClickHouse/pull/13745) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Added docker image for style check. Added style check that all docker and docker compose files are located in docker directory. [#13724](https://github.com/ClickHouse/ClickHouse/pull/13724) ([Ilya Yatsishin](https://github.com/qoega)).
* Fix cassandra build on Mac OS. [#13708](https://github.com/ClickHouse/ClickHouse/pull/13708) ([Ilya Yatsishin](https://github.com/qoega)).
* Fix link error in shared build. [#13700](https://github.com/ClickHouse/ClickHouse/pull/13700) ([Amos Bird](https://github.com/amosbird)).
* Updating LDAP user authentication suite to check that it works with RBAC. [#13656](https://github.com/ClickHouse/ClickHouse/pull/13656) ([vzakaznikov](https://github.com/vzakaznikov)).
* Removed `-DENABLE_CURL_CLIENT` for `contrib/aws`. [#13628](https://github.com/ClickHouse/ClickHouse/pull/13628) ([Vladimir Chebotarev](https://github.com/excitoon)).
* Increasing health-check timeouts for ClickHouse nodes and adding support to dump docker-compose logs if unhealthy containers found. [#13612](https://github.com/ClickHouse/ClickHouse/pull/13612) ([vzakaznikov](https://github.com/vzakaznikov)).
* Make sure https://github.com/ClickHouse/ClickHouse/issues/10977 is invalid. [#13539](https://github.com/ClickHouse/ClickHouse/pull/13539) ([Amos Bird](https://github.com/amosbird)).
* Skip PR's from robot-clickhouse. [#13489](https://github.com/ClickHouse/ClickHouse/pull/13489) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Move Dockerfiles from integration tests to `docker/test` directory. docker_compose files are available in `runner` docker container. Docker images are built in CI and not in integration tests. [#13448](https://github.com/ClickHouse/ClickHouse/pull/13448) ([Ilya Yatsishin](https://github.com/qoega)).
## ClickHouse release 20.7
### ClickHouse release v20.7.2.30-stable, 2020-08-31
#### Backward Incompatible Change
* Function `modulo` (operator `%`) with at least one floating point number as argument will calculate remainder of division directly on floating point numbers without converting both arguments to integers. It makes behaviour compatible with most of DBMS. This also applicable for Date and DateTime data types. Added alias `mod`. This closes [#7323](https://github.com/ClickHouse/ClickHouse/issues/7323). [#12585](https://github.com/ClickHouse/ClickHouse/pull/12585) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Deprecate special printing of zero Date/DateTime values as `0000-00-00` and `0000-00-00 00:00:00`. [#12442](https://github.com/ClickHouse/ClickHouse/pull/12442) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* The function `groupArrayMoving*` was not working for distributed queries. It's result was calculated within incorrect data type (without promotion to the largest type). The function `groupArrayMovingAvg` was returning integer number that was inconsistent with the `avg` function. This fixes [#12568](https://github.com/ClickHouse/ClickHouse/issues/12568). [#12622](https://github.com/ClickHouse/ClickHouse/pull/12622) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add sanity check for MergeTree settings. If the settings are incorrect, the server will refuse to start or to create a table, printing detailed explanation to the user. [#13153](https://github.com/ClickHouse/ClickHouse/pull/13153) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Protect from the cases when user may set `background_pool_size` to value lower than `number_of_free_entries_in_pool_to_execute_mutation` or `number_of_free_entries_in_pool_to_lower_max_size_of_merge`. In these cases ALTERs won't work or the maximum size of merge will be too limited. It will throw exception explaining what to do. This closes [#10897](https://github.com/ClickHouse/ClickHouse/issues/10897). [#12728](https://github.com/ClickHouse/ClickHouse/pull/12728) ([alexey-milovidov](https://github.com/alexey-milovidov)).
#### New Feature
* Polygon dictionary type that provides efficient "reverse geocoding" lookups - to find the region by coordinates in a dictionary of many polygons (world map). It is using carefully optimized algorithm with recursive grids to maintain low CPU and memory usage. [#9278](https://github.com/ClickHouse/ClickHouse/pull/9278) ([achulkov2](https://github.com/achulkov2)).
* Added support of LDAP authentication for preconfigured users ("Simple Bind" method). [#11234](https://github.com/ClickHouse/ClickHouse/pull/11234) ([Denis Glazachev](https://github.com/traceon)).
* Introduce setting `alter_partition_verbose_result` which outputs information about touched parts for some types of `ALTER TABLE ... PARTITION ...` queries (currently `ATTACH` and `FREEZE`). Closes [#8076](https://github.com/ClickHouse/ClickHouse/issues/8076). [#13017](https://github.com/ClickHouse/ClickHouse/pull/13017) ([alesapin](https://github.com/alesapin)).
* Add `bayesAB` function for bayesian-ab-testing. [#12327](https://github.com/ClickHouse/ClickHouse/pull/12327) ([achimbab](https://github.com/achimbab)).
* Added `system.crash_log` table into which stack traces for fatal errors are collected. This table should be empty. [#12316](https://github.com/ClickHouse/ClickHouse/pull/12316) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Added http headers `X-ClickHouse-Database` and `X-ClickHouse-Format` which may be used to set default database and output format. [#12981](https://github.com/ClickHouse/ClickHouse/pull/12981) ([hcz](https://github.com/hczhcz)).
* Add `minMap` and `maxMap` functions support to `SimpleAggregateFunction`. [#12662](https://github.com/ClickHouse/ClickHouse/pull/12662) ([Ildus Kurbangaliev](https://github.com/ildus)).
* Add setting `allow_non_metadata_alters` which restricts to execute `ALTER` queries which modify data on disk. Disabled be default. Closes [#11547](https://github.com/ClickHouse/ClickHouse/issues/11547). [#12635](https://github.com/ClickHouse/ClickHouse/pull/12635) ([alesapin](https://github.com/alesapin)).
* A function `formatRow` is added to support turning arbitrary expressions into a string via given format. It's useful for manipulating SQL outputs and is quite versatile combined with the `columns` function. [#12574](https://github.com/ClickHouse/ClickHouse/pull/12574) ([Amos Bird](https://github.com/amosbird)).
* Add `FROM_UNIXTIME` function for compatibility with MySQL, related to [12149](https://github.com/ClickHouse/ClickHouse/issues/12149). [#12484](https://github.com/ClickHouse/ClickHouse/pull/12484) ([flynn](https://github.com/ucasFL)).
* Allow Nullable types as keys in MergeTree tables if `allow_nullable_key` table setting is enabled. Closes [#5319](https://github.com/ClickHouse/ClickHouse/issues/5319). [#12433](https://github.com/ClickHouse/ClickHouse/pull/12433) ([Amos Bird](https://github.com/amosbird)).
* Integration with [COS](https://intl.cloud.tencent.com/product/cos). [#12386](https://github.com/ClickHouse/ClickHouse/pull/12386) ([fastio](https://github.com/fastio)).
* Add mapAdd and mapSubtract functions for adding/subtracting key-mapped values. [#11735](https://github.com/ClickHouse/ClickHouse/pull/11735) ([Ildus Kurbangaliev](https://github.com/ildus)).
#### Bug Fix
* Fix premature `ON CLUSTER` timeouts for queries that must be executed on a single replica. Fixes [#6704](https://github.com/ClickHouse/ClickHouse/issues/6704), [#7228](https://github.com/ClickHouse/ClickHouse/issues/7228), [#13361](https://github.com/ClickHouse/ClickHouse/issues/13361), [#11884](https://github.com/ClickHouse/ClickHouse/issues/11884). [#13450](https://github.com/ClickHouse/ClickHouse/pull/13450) ([alesapin](https://github.com/alesapin)).
* Fix crash in mark inclusion search introduced in [#12277](https://github.com/ClickHouse/ClickHouse/pull/12277). [#14225](https://github.com/ClickHouse/ClickHouse/pull/14225) ([Amos Bird](https://github.com/amosbird)).
* Fix race condition in external dictionaries with cache layout which can lead server crash. [#12566](https://github.com/ClickHouse/ClickHouse/pull/12566) ([alesapin](https://github.com/alesapin)).
* Fix visible data clobbering by progress bar in client in interactive mode. This fixes [#12562](https://github.com/ClickHouse/ClickHouse/issues/12562) and [#13369](https://github.com/ClickHouse/ClickHouse/issues/13369) and [#13584](https://github.com/ClickHouse/ClickHouse/issues/13584) and fixes [#12964](https://github.com/ClickHouse/ClickHouse/issues/12964). [#13691](https://github.com/ClickHouse/ClickHouse/pull/13691) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fixed incorrect sorting order for `LowCardinality` columns when ORDER BY multiple columns is used. This fixes [#13958](https://github.com/ClickHouse/ClickHouse/issues/13958). [#14223](https://github.com/ClickHouse/ClickHouse/pull/14223) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Removed hardcoded timeout, which wrongly overruled `query_wait_timeout_milliseconds` setting for cache-dictionary. [#14105](https://github.com/ClickHouse/ClickHouse/pull/14105) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Fixed wrong mount point in extra info for `Poco::Exception: no space left on device`. [#14050](https://github.com/ClickHouse/ClickHouse/pull/14050) ([tavplubix](https://github.com/tavplubix)).
* Fix wrong query optimization of select queries with `DISTINCT` keyword when subqueries also have `DISTINCT` in case `optimize_duplicate_order_by_and_distinct` setting is enabled. [#13925](https://github.com/ClickHouse/ClickHouse/pull/13925) ([Artem Zuikov](https://github.com/4ertus2)).
* Fixed potential deadlock when renaming `Distributed` table. [#13922](https://github.com/ClickHouse/ClickHouse/pull/13922) ([tavplubix](https://github.com/tavplubix)).
* Fix incorrect sorting for `FixedString` columns when ORDER BY multiple columns is used. Fixes [#13182](https://github.com/ClickHouse/ClickHouse/issues/13182). [#13887](https://github.com/ClickHouse/ClickHouse/pull/13887) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix potentially lower precision of `topK`/`topKWeighted` aggregations (with non-default parameters). [#13817](https://github.com/ClickHouse/ClickHouse/pull/13817) ([Azat Khuzhin](https://github.com/azat)).
* Fix reading from MergeTree table with INDEX of type SET fails when compared against NULL. This fixes [#13686](https://github.com/ClickHouse/ClickHouse/issues/13686). [#13793](https://github.com/ClickHouse/ClickHouse/pull/13793) ([Amos Bird](https://github.com/amosbird)).
* Fix step overflow in function `range()`. [#13790](https://github.com/ClickHouse/ClickHouse/pull/13790) ([Azat Khuzhin](https://github.com/azat)).
* Fixed `Directory not empty` error when concurrently executing `DROP DATABASE` and `CREATE TABLE`. [#13756](https://github.com/ClickHouse/ClickHouse/pull/13756) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add range check for `h3KRing` function. This fixes [#13633](https://github.com/ClickHouse/ClickHouse/issues/13633). [#13752](https://github.com/ClickHouse/ClickHouse/pull/13752) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix race condition between DETACH and background merges. Parts may revive after detach. This is continuation of [#8602](https://github.com/ClickHouse/ClickHouse/issues/8602) that did not fix the issue but introduced a test that started to fail in very rare cases, demonstrating the issue. [#13746](https://github.com/ClickHouse/ClickHouse/pull/13746) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix logging Settings.Names/Values when `log_queries_min_type` greater than `QUERY_START`. [#13737](https://github.com/ClickHouse/ClickHouse/pull/13737) ([Azat Khuzhin](https://github.com/azat)).
* Fix incorrect message in `clickhouse-server.init` while checking user and group. [#13711](https://github.com/ClickHouse/ClickHouse/pull/13711) ([ylchou](https://github.com/ylchou)).
* Do not optimize `any(arrayJoin())` to `arrayJoin()` under `optimize_move_functions_out_of_any`. [#13681](https://github.com/ClickHouse/ClickHouse/pull/13681) ([Azat Khuzhin](https://github.com/azat)).
* Fixed possible deadlock in concurrent `ALTER ... REPLACE/MOVE PARTITION ...` queries. [#13626](https://github.com/ClickHouse/ClickHouse/pull/13626) ([tavplubix](https://github.com/tavplubix)).
* Fixed the behaviour when sometimes cache-dictionary returned default value instead of present value from source. [#13624](https://github.com/ClickHouse/ClickHouse/pull/13624) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Fix secondary indices corruption in compact parts (compact parts is an experimental feature). [#13538](https://github.com/ClickHouse/ClickHouse/pull/13538) ([Anton Popov](https://github.com/CurtizJ)).
* Fix wrong code in function `netloc`. This fixes [#13335](https://github.com/ClickHouse/ClickHouse/issues/13335). [#13446](https://github.com/ClickHouse/ClickHouse/pull/13446) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix error in `parseDateTimeBestEffort` function when unix timestamp was passed as an argument. This fixes [#13362](https://github.com/ClickHouse/ClickHouse/issues/13362). [#13441](https://github.com/ClickHouse/ClickHouse/pull/13441) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix invalid return type for comparison of tuples with `NULL` elements. Fixes [#12461](https://github.com/ClickHouse/ClickHouse/issues/12461). [#13420](https://github.com/ClickHouse/ClickHouse/pull/13420) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix wrong optimization caused `aggregate function any(x) is found inside another aggregate function in query` error with `SET optimize_move_functions_out_of_any = 1` and aliases inside `any()`. [#13419](https://github.com/ClickHouse/ClickHouse/pull/13419) ([Artem Zuikov](https://github.com/4ertus2)).
* Fix possible race in `StorageMemory`. [#13416](https://github.com/ClickHouse/ClickHouse/pull/13416) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix empty output for `Arrow` and `Parquet` formats in case if query return zero rows. It was done because empty output is not valid for this formats. [#13399](https://github.com/ClickHouse/ClickHouse/pull/13399) ([hcz](https://github.com/hczhcz)).
* Fix select queries with constant columns and prefix of primary key in `ORDER BY` clause. [#13396](https://github.com/ClickHouse/ClickHouse/pull/13396) ([Anton Popov](https://github.com/CurtizJ)).
* Fix `PrettyCompactMonoBlock` for clickhouse-local. Fix extremes/totals with `PrettyCompactMonoBlock`. Fixes [#7746](https://github.com/ClickHouse/ClickHouse/issues/7746). [#13394](https://github.com/ClickHouse/ClickHouse/pull/13394) ([Azat Khuzhin](https://github.com/azat)).
* Fixed deadlock in system.text_log. [#12452](https://github.com/ClickHouse/ClickHouse/pull/12452) ([alexey-milovidov](https://github.com/alexey-milovidov)). It is a part of [#12339](https://github.com/ClickHouse/ClickHouse/issues/12339). This fixes [#12325](https://github.com/ClickHouse/ClickHouse/issues/12325). [#13386](https://github.com/ClickHouse/ClickHouse/pull/13386) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Fixed `File(TSVWithNames*)` (header was written multiple times), fixed `clickhouse-local --format CSVWithNames*` (lacks header, broken after [#12197](https://github.com/ClickHouse/ClickHouse/issues/12197)), fixed `clickhouse-local --format CSVWithNames*` with zero rows (lacks header). [#13343](https://github.com/ClickHouse/ClickHouse/pull/13343) ([Azat Khuzhin](https://github.com/azat)).
* Fix segfault when function `groupArrayMovingSum` deserializes empty state. Fixes [#13339](https://github.com/ClickHouse/ClickHouse/issues/13339). [#13341](https://github.com/ClickHouse/ClickHouse/pull/13341) ([alesapin](https://github.com/alesapin)).
* Throw error on `arrayJoin()` function in `JOIN ON` section. [#13330](https://github.com/ClickHouse/ClickHouse/pull/13330) ([Artem Zuikov](https://github.com/4ertus2)).
* Fix crash in `LEFT ASOF JOIN` with `join_use_nulls=1`. [#13291](https://github.com/ClickHouse/ClickHouse/pull/13291) ([Artem Zuikov](https://github.com/4ertus2)).
* Fix possible error `Totals having transform was already added to pipeline` in case of a query from delayed replica. [#13290](https://github.com/ClickHouse/ClickHouse/pull/13290) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* The server may crash if user passed specifically crafted arguments to the function `h3ToChildren`. This fixes [#13275](https://github.com/ClickHouse/ClickHouse/issues/13275). [#13277](https://github.com/ClickHouse/ClickHouse/pull/13277) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix potentially low performance and slightly incorrect result for `uniqExact`, `topK`, `sumDistinct` and similar aggregate functions called on Float types with `NaN` values. It also triggered assert in debug build. This fixes [#12491](https://github.com/ClickHouse/ClickHouse/issues/12491). [#13254](https://github.com/ClickHouse/ClickHouse/pull/13254) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix assertion in KeyCondition when primary key contains expression with monotonic function and query contains comparison with constant whose type is different. This fixes [#12465](https://github.com/ClickHouse/ClickHouse/issues/12465). [#13251](https://github.com/ClickHouse/ClickHouse/pull/13251) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Return passed number for numbers with MSB set in function roundUpToPowerOfTwoOrZero(). It prevents potential errors in case of overflow of array sizes. [#13234](https://github.com/ClickHouse/ClickHouse/pull/13234) ([Azat Khuzhin](https://github.com/azat)).
* Fix function if with nullable constexpr as cond that is not literal NULL. Fixes [#12463](https://github.com/ClickHouse/ClickHouse/issues/12463). [#13226](https://github.com/ClickHouse/ClickHouse/pull/13226) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix assert in `arrayElement` function in case of array elements are Nullable and array subscript is also Nullable. This fixes [#12172](https://github.com/ClickHouse/ClickHouse/issues/12172). [#13224](https://github.com/ClickHouse/ClickHouse/pull/13224) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix DateTime64 conversion functions with constant argument. [#13205](https://github.com/ClickHouse/ClickHouse/pull/13205) ([Azat Khuzhin](https://github.com/azat)).
* Fix parsing row policies from users.xml when names of databases or tables contain dots. This fixes [#5779](https://github.com/ClickHouse/ClickHouse/issues/5779), [#12527](https://github.com/ClickHouse/ClickHouse/issues/12527). [#13199](https://github.com/ClickHouse/ClickHouse/pull/13199) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix access to `redis` dictionary after connection was dropped once. It may happen with `cache` and `direct` dictionary layouts. [#13082](https://github.com/ClickHouse/ClickHouse/pull/13082) ([Anton Popov](https://github.com/CurtizJ)).
* Fix wrong index analysis with functions. It could lead to some data parts being skipped when reading from `MergeTree` tables. Fixes [#13060](https://github.com/ClickHouse/ClickHouse/issues/13060). Fixes [#12406](https://github.com/ClickHouse/ClickHouse/issues/12406). [#13081](https://github.com/ClickHouse/ClickHouse/pull/13081) ([Anton Popov](https://github.com/CurtizJ)).
* Fix error `Cannot convert column because it is constant but values of constants are different in source and result` for remote queries which use deterministic functions in scope of query, but not deterministic between queries, like `now()`, `now64()`, `randConstant()`. Fixes [#11327](https://github.com/ClickHouse/ClickHouse/issues/11327). [#13075](https://github.com/ClickHouse/ClickHouse/pull/13075) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix crash which was possible for queries with `ORDER BY` tuple and small `LIMIT`. Fixes [#12623](https://github.com/ClickHouse/ClickHouse/issues/12623). [#13009](https://github.com/ClickHouse/ClickHouse/pull/13009) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix `Block structure mismatch` error for queries with `UNION` and `JOIN`. Fixes [#12602](https://github.com/ClickHouse/ClickHouse/issues/12602). [#12989](https://github.com/ClickHouse/ClickHouse/pull/12989) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Corrected `merge_with_ttl_timeout` logic which did not work well when expiration affected more than one partition over one time interval. (Authored by @excitoon). [#12982](https://github.com/ClickHouse/ClickHouse/pull/12982) ([Alexander Kazakov](https://github.com/Akazz)).
* Fix columns duplication for range hashed dictionary created from DDL query. This fixes [#10605](https://github.com/ClickHouse/ClickHouse/issues/10605). [#12857](https://github.com/ClickHouse/ClickHouse/pull/12857) ([alesapin](https://github.com/alesapin)).
* Fix unnecessary limiting for the number of threads for selects from local replica. [#12840](https://github.com/ClickHouse/ClickHouse/pull/12840) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix rare bug when `ALTER DELETE` and `ALTER MODIFY COLUMN` queries executed simultaneously as a single mutation. Bug leads to an incorrect amount of rows in `count.txt` and as a consequence incorrect data in part. Also, fix a small bug with simultaneous `ALTER RENAME COLUMN` and `ALTER ADD COLUMN`. [#12760](https://github.com/ClickHouse/ClickHouse/pull/12760) ([alesapin](https://github.com/alesapin)).
* Wrong credentials being used when using `clickhouse` dictionary source to query remote tables. [#12756](https://github.com/ClickHouse/ClickHouse/pull/12756) ([sundyli](https://github.com/sundy-li)).
* Fix `CAST(Nullable(String), Enum())`. [#12745](https://github.com/ClickHouse/ClickHouse/pull/12745) ([Azat Khuzhin](https://github.com/azat)).
* Fix performance with large tuples, which are interpreted as functions in `IN` section. The case when user writes `WHERE x IN tuple(1, 2, ...)` instead of `WHERE x IN (1, 2, ...)` for some obscure reason. [#12700](https://github.com/ClickHouse/ClickHouse/pull/12700) ([Anton Popov](https://github.com/CurtizJ)).
* Fix memory tracking for input_format_parallel_parsing (by attaching thread to group). [#12672](https://github.com/ClickHouse/ClickHouse/pull/12672) ([Azat Khuzhin](https://github.com/azat)).
* Fix wrong optimization `optimize_move_functions_out_of_any=1` in case of `any(func(<lambda>))`. [#12664](https://github.com/ClickHouse/ClickHouse/pull/12664) ([Artem Zuikov](https://github.com/4ertus2)).
* Fixed [#10572](https://github.com/ClickHouse/ClickHouse/issues/10572) fix bloom filter index with const expression. [#12659](https://github.com/ClickHouse/ClickHouse/pull/12659) ([Winter Zhang](https://github.com/zhang2014)).
* Fix SIGSEGV in StorageKafka when broker is unavailable (and not only). [#12658](https://github.com/ClickHouse/ClickHouse/pull/12658) ([Azat Khuzhin](https://github.com/azat)).
* Add support for function `if` with `Array(UUID)` arguments. This fixes [#11066](https://github.com/ClickHouse/ClickHouse/issues/11066). [#12648](https://github.com/ClickHouse/ClickHouse/pull/12648) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* CREATE USER IF NOT EXISTS now doesn't throw exception if the user exists. This fixes [#12507](https://github.com/ClickHouse/ClickHouse/issues/12507). [#12646](https://github.com/ClickHouse/ClickHouse/pull/12646) ([Vitaly Baranov](https://github.com/vitlibar)).
* Exception `There is no supertype...` can be thrown during `ALTER ... UPDATE` in unexpected cases (e.g. when subtracting from UInt64 column). This fixes [#7306](https://github.com/ClickHouse/ClickHouse/issues/7306). This fixes [#4165](https://github.com/ClickHouse/ClickHouse/issues/4165). [#12633](https://github.com/ClickHouse/ClickHouse/pull/12633) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix possible `Pipeline stuck` error for queries with external sorting. Fixes [#12617](https://github.com/ClickHouse/ClickHouse/issues/12617). [#12618](https://github.com/ClickHouse/ClickHouse/pull/12618) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix error `Output of TreeExecutor is not sorted` for `OPTIMIZE DEDUPLICATE`. Fixes [#11572](https://github.com/ClickHouse/ClickHouse/issues/11572). [#12613](https://github.com/ClickHouse/ClickHouse/pull/12613) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix the issue when alias on result of function `any` can be lost during query optimization. [#12593](https://github.com/ClickHouse/ClickHouse/pull/12593) ([Anton Popov](https://github.com/CurtizJ)).
* Remove data for Distributed tables (blocks from async INSERTs) on DROP TABLE. [#12556](https://github.com/ClickHouse/ClickHouse/pull/12556) ([Azat Khuzhin](https://github.com/azat)).
* Now ClickHouse will recalculate checksums for parts when file `checksums.txt` is absent. Broken since [#9827](https://github.com/ClickHouse/ClickHouse/issues/9827). [#12545](https://github.com/ClickHouse/ClickHouse/pull/12545) ([alesapin](https://github.com/alesapin)).
* Fix bug which lead to broken old parts after `ALTER DELETE` query when `enable_mixed_granularity_parts=1`. Fixes [#12536](https://github.com/ClickHouse/ClickHouse/issues/12536). [#12543](https://github.com/ClickHouse/ClickHouse/pull/12543) ([alesapin](https://github.com/alesapin)).
* Fixing race condition in live view tables which could cause data duplication. LIVE VIEW is an experimental feature. [#12519](https://github.com/ClickHouse/ClickHouse/pull/12519) ([vzakaznikov](https://github.com/vzakaznikov)).
* Fix backwards compatibility in binary format of `AggregateFunction(avg, ...)` values. This fixes [#12342](https://github.com/ClickHouse/ClickHouse/issues/12342). [#12486](https://github.com/ClickHouse/ClickHouse/pull/12486) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix crash in JOIN with dictionary when we are joining over expression of dictionary key: `t JOIN dict ON expr(dict.id) = t.id`. Disable dictionary join optimisation for this case. [#12458](https://github.com/ClickHouse/ClickHouse/pull/12458) ([Artem Zuikov](https://github.com/4ertus2)).
* Fix overflow when very large LIMIT or OFFSET is specified. This fixes [#10470](https://github.com/ClickHouse/ClickHouse/issues/10470). This fixes [#11372](https://github.com/ClickHouse/ClickHouse/issues/11372). [#12427](https://github.com/ClickHouse/ClickHouse/pull/12427) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* kafka: fix SIGSEGV if there is a message with error in the middle of the batch. [#12302](https://github.com/ClickHouse/ClickHouse/pull/12302) ([Azat Khuzhin](https://github.com/azat)).
#### Improvement
* Keep smaller amount of logs in ZooKeeper. Avoid excessive growing of ZooKeeper nodes in case of offline replicas when having many servers/tables/inserts. [#13100](https://github.com/ClickHouse/ClickHouse/pull/13100) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Now exceptions forwarded to the client if an error happened during ALTER or mutation. Closes [#11329](https://github.com/ClickHouse/ClickHouse/issues/11329). [#12666](https://github.com/ClickHouse/ClickHouse/pull/12666) ([alesapin](https://github.com/alesapin)).
* Add `QueryTimeMicroseconds`, `SelectQueryTimeMicroseconds` and `InsertQueryTimeMicroseconds` to `system.events`, along with system.metrics, processes, query_log, etc. [#13028](https://github.com/ClickHouse/ClickHouse/pull/13028) ([ianton-ru](https://github.com/ianton-ru)).
* Added `SelectedRows` and `SelectedBytes` to `system.events`, along with system.metrics, processes, query_log, etc. [#12638](https://github.com/ClickHouse/ClickHouse/pull/12638) ([ianton-ru](https://github.com/ianton-ru)).
* Added `current_database` information to `system.query_log`. [#12652](https://github.com/ClickHouse/ClickHouse/pull/12652) ([Amos Bird](https://github.com/amosbird)).
* Allow `TabSeparatedRaw` as input format. [#12009](https://github.com/ClickHouse/ClickHouse/pull/12009) ([hcz](https://github.com/hczhcz)).
* Now `joinGet` supports multi-key lookup. [#12418](https://github.com/ClickHouse/ClickHouse/pull/12418) ([Amos Bird](https://github.com/amosbird)).
* Allow `*Map` aggregate functions to work on Arrays with NULLs. Fixes [#13157](https://github.com/ClickHouse/ClickHouse/issues/13157). [#13225](https://github.com/ClickHouse/ClickHouse/pull/13225) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Avoid overflow in parsing of DateTime values that will lead to negative unix timestamp in their timezone (for example, `1970-01-01 00:00:00` in Moscow). Saturate to zero instead. This fixes [#3470](https://github.com/ClickHouse/ClickHouse/issues/3470). This fixes [#4172](https://github.com/ClickHouse/ClickHouse/issues/4172). [#12443](https://github.com/ClickHouse/ClickHouse/pull/12443) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* AvroConfluent: Skip Kafka tombstone records - Support skipping broken records [#13203](https://github.com/ClickHouse/ClickHouse/pull/13203) ([Andrew Onyshchuk](https://github.com/oandrew)).
* Fix wrong error for long queries. It was possible to get syntax error other than `Max query size exceeded` for correct query. [#13928](https://github.com/ClickHouse/ClickHouse/pull/13928) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix data race in `lgamma` function. This race was caught only in `tsan`, no side effects really happened. [#13842](https://github.com/ClickHouse/ClickHouse/pull/13842) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix a 'Week'-interval formatting for ATTACH/ALTER/CREATE QUOTA-statements. [#13417](https://github.com/ClickHouse/ClickHouse/pull/13417) ([vladimir-golovchenko](https://github.com/vladimir-golovchenko)).
* Now broken parts are also reported when encountered in compact part processing. Compact parts is an experimental feature. [#13282](https://github.com/ClickHouse/ClickHouse/pull/13282) ([Amos Bird](https://github.com/amosbird)).
* Fix assert in `geohashesInBox`. This fixes [#12554](https://github.com/ClickHouse/ClickHouse/issues/12554). [#13229](https://github.com/ClickHouse/ClickHouse/pull/13229) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix assert in `parseDateTimeBestEffort`. This fixes [#12649](https://github.com/ClickHouse/ClickHouse/issues/12649). [#13227](https://github.com/ClickHouse/ClickHouse/pull/13227) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Minor optimization in Processors/PipelineExecutor: breaking out of a loop because it makes sense to do so. [#13058](https://github.com/ClickHouse/ClickHouse/pull/13058) ([Mark Papadakis](https://github.com/markpapadakis)).
* Support TRUNCATE table without TABLE keyword. [#12653](https://github.com/ClickHouse/ClickHouse/pull/12653) ([Winter Zhang](https://github.com/zhang2014)).
* Fix explain query format overwrite by default. This fixes [#12541](https://github.com/ClickHouse/ClickHouse/issues/12432). [#12541](https://github.com/ClickHouse/ClickHouse/pull/12541) ([BohuTANG](https://github.com/BohuTANG)).
* Allow to set JOIN kind and type in more standad way: `LEFT SEMI JOIN` instead of `SEMI LEFT JOIN`. For now both are correct. [#12520](https://github.com/ClickHouse/ClickHouse/pull/12520) ([Artem Zuikov](https://github.com/4ertus2)).
* Changes default value for `multiple_joins_rewriter_version` to 2. It enables new multiple joins rewriter that knows about column names. [#12469](https://github.com/ClickHouse/ClickHouse/pull/12469) ([Artem Zuikov](https://github.com/4ertus2)).
* Add several metrics for requests to S3 storages. [#12464](https://github.com/ClickHouse/ClickHouse/pull/12464) ([ianton-ru](https://github.com/ianton-ru)).
* Use correct default secure port for clickhouse-benchmark with `--secure` argument. This fixes [#11044](https://github.com/ClickHouse/ClickHouse/issues/11044). [#12440](https://github.com/ClickHouse/ClickHouse/pull/12440) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Rollback insertion errors in `Log`, `TinyLog`, `StripeLog` engines. In previous versions insertion error lead to inconsisent table state (this works as documented and it is normal for these table engines). This fixes [#12402](https://github.com/ClickHouse/ClickHouse/issues/12402). [#12426](https://github.com/ClickHouse/ClickHouse/pull/12426) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Implement `RENAME DATABASE` and `RENAME DICTIONARY` for `Atomic` database engine - Add implicit `{uuid}` macro, which can be used in ZooKeeper path for `ReplicatedMergeTree`. It works with `CREATE ... ON CLUSTER ...` queries. Set `show_table_uuid_in_table_create_query_if_not_nil` to `true` to use it. - Make `ReplicatedMergeTree` engine arguments optional, `/clickhouse/tables/{uuid}/{shard}/` and `{replica}` are used by default. Closes [#12135](https://github.com/ClickHouse/ClickHouse/issues/12135). - Minor fixes. - These changes break backward compatibility of `Atomic` database engine. Previously created `Atomic` databases must be manually converted to new format. Atomic database is an experimental feature. [#12343](https://github.com/ClickHouse/ClickHouse/pull/12343) ([tavplubix](https://github.com/tavplubix)).
* Separated `AWSAuthV4Signer` into different logger, removed excessive `AWSClient: AWSClient` from log messages. [#12320](https://github.com/ClickHouse/ClickHouse/pull/12320) ([Vladimir Chebotarev](https://github.com/excitoon)).
* Better exception message in disk access storage. [#12625](https://github.com/ClickHouse/ClickHouse/pull/12625) ([alesapin](https://github.com/alesapin)).
* Better exception for function `in` with invalid number of arguments. [#12529](https://github.com/ClickHouse/ClickHouse/pull/12529) ([Anton Popov](https://github.com/CurtizJ)).
* Fix error message about adaptive granularity. [#12624](https://github.com/ClickHouse/ClickHouse/pull/12624) ([alesapin](https://github.com/alesapin)).
* Fix SETTINGS parse after FORMAT. [#12480](https://github.com/ClickHouse/ClickHouse/pull/12480) ([Azat Khuzhin](https://github.com/azat)).
* If MergeTree table does not contain ORDER BY or PARTITION BY, it was possible to request ALTER to CLEAR all the columns and ALTER will stuck. Fixed [#7941](https://github.com/ClickHouse/ClickHouse/issues/7941). [#12382](https://github.com/ClickHouse/ClickHouse/pull/12382) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Avoid re-loading completion from the history file after each query (to avoid history overlaps with other client sessions). [#13086](https://github.com/ClickHouse/ClickHouse/pull/13086) ([Azat Khuzhin](https://github.com/azat)).
#### Performance Improvement
* Lower memory usage for some operations up to 2 times. [#12424](https://github.com/ClickHouse/ClickHouse/pull/12424) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Optimize PK lookup for queries that match exact PK range. [#12277](https://github.com/ClickHouse/ClickHouse/pull/12277) ([Ivan Babrou](https://github.com/bobrik)).
* Slightly optimize very short queries with `LowCardinality`. [#14129](https://github.com/ClickHouse/ClickHouse/pull/14129) ([Anton Popov](https://github.com/CurtizJ)).
* Slightly improve performance of aggregation by UInt8/UInt16 keys. [#13091](https://github.com/ClickHouse/ClickHouse/pull/13091) and [#13055](https://github.com/ClickHouse/ClickHouse/pull/13055) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Push down `LIMIT` step for query plan (inside subqueries). [#13016](https://github.com/ClickHouse/ClickHouse/pull/13016) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Parallel primary key lookup and skipping index stages on parts, as described in [#11564](https://github.com/ClickHouse/ClickHouse/issues/11564). [#12589](https://github.com/ClickHouse/ClickHouse/pull/12589) ([Ivan Babrou](https://github.com/bobrik)).
* Converting String-type arguments of function "if" and "transform" into enum if `set optimize_if_transform_strings_to_enum = 1`. [#12515](https://github.com/ClickHouse/ClickHouse/pull/12515) ([Artem Zuikov](https://github.com/4ertus2)).
* Replaces monotonic functions with its argument in `ORDER BY` if `set optimize_monotonous_functions_in_order_by=1`. [#12467](https://github.com/ClickHouse/ClickHouse/pull/12467) ([Artem Zuikov](https://github.com/4ertus2)).
* Add order by optimization that rewrites `ORDER BY x, f(x)` with `ORDER by x` if `set optimize_redundant_functions_in_order_by = 1`. [#12404](https://github.com/ClickHouse/ClickHouse/pull/12404) ([Artem Zuikov](https://github.com/4ertus2)).
* Allow pushdown predicate when subquery contains `WITH` clause. This fixes [#12293](https://github.com/ClickHouse/ClickHouse/issues/12293) [#12663](https://github.com/ClickHouse/ClickHouse/pull/12663) ([Winter Zhang](https://github.com/zhang2014)).
* Improve performance of reading from compact parts. Compact parts is an experimental feature. [#12492](https://github.com/ClickHouse/ClickHouse/pull/12492) ([Anton Popov](https://github.com/CurtizJ)).
* Attempt to implement streaming optimization in `DiskS3`. DiskS3 is an experimental feature. [#12434](https://github.com/ClickHouse/ClickHouse/pull/12434) ([Vladimir Chebotarev](https://github.com/excitoon)).
#### Build/Testing/Packaging Improvement
* Use `shellcheck` for sh tests linting. [#13200](https://github.com/ClickHouse/ClickHouse/pull/13200) [#13207](https://github.com/ClickHouse/ClickHouse/pull/13207) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add script which set labels for pull requests in GitHub hook. [#13183](https://github.com/ClickHouse/ClickHouse/pull/13183) ([alesapin](https://github.com/alesapin)).
* Remove some of recursive submodules. See [#13378](https://github.com/ClickHouse/ClickHouse/issues/13378). [#13379](https://github.com/ClickHouse/ClickHouse/pull/13379) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Ensure that all the submodules are from proper URLs. Continuation of [#13379](https://github.com/ClickHouse/ClickHouse/issues/13379). This fixes [#13378](https://github.com/ClickHouse/ClickHouse/issues/13378). [#13397](https://github.com/ClickHouse/ClickHouse/pull/13397) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Added support for user-declared settings, which can be accessed from inside queries. This is needed when ClickHouse engine is used as a component of another system. [#13013](https://github.com/ClickHouse/ClickHouse/pull/13013) ([Vitaly Baranov](https://github.com/vitlibar)).
* Added testing for RBAC functionality of INSERT privilege in TestFlows. Expanded tables on which SELECT is being tested. Added Requirements to match new table engine tests. [#13340](https://github.com/ClickHouse/ClickHouse/pull/13340) ([MyroTk](https://github.com/MyroTk)).
* Fix timeout error during server restart in the stress test. [#13321](https://github.com/ClickHouse/ClickHouse/pull/13321) ([alesapin](https://github.com/alesapin)).
* Now fast test will wait server with retries. [#13284](https://github.com/ClickHouse/ClickHouse/pull/13284) ([alesapin](https://github.com/alesapin)).
* Function `materialize()` (the function for ClickHouse testing) will work for NULL as expected - by transforming it to non-constant column. [#13212](https://github.com/ClickHouse/ClickHouse/pull/13212) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix libunwind build in AArch64. This fixes [#13204](https://github.com/ClickHouse/ClickHouse/issues/13204). [#13208](https://github.com/ClickHouse/ClickHouse/pull/13208) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Even more retries in zkutil gtest to prevent test flakiness. [#13165](https://github.com/ClickHouse/ClickHouse/pull/13165) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Small fixes to the RBAC TestFlows. [#13152](https://github.com/ClickHouse/ClickHouse/pull/13152) ([vzakaznikov](https://github.com/vzakaznikov)).
* Fixing `00960_live_view_watch_events_live.py` test. [#13108](https://github.com/ClickHouse/ClickHouse/pull/13108) ([vzakaznikov](https://github.com/vzakaznikov)).
* Improve cache purge in documentation deploy script. [#13107](https://github.com/ClickHouse/ClickHouse/pull/13107) ([alesapin](https://github.com/alesapin)).
* Rewrote some orphan tests to gtest. Removed useless includes from tests. [#13073](https://github.com/ClickHouse/ClickHouse/pull/13073) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Added tests for RBAC functionality of `SELECT` privilege in TestFlows. [#13061](https://github.com/ClickHouse/ClickHouse/pull/13061) ([Ritaank Tiwari](https://github.com/ritaank)).
* Rerun some tests in fast test check. [#12992](https://github.com/ClickHouse/ClickHouse/pull/12992) ([alesapin](https://github.com/alesapin)).
* Fix MSan error in "rdkafka" library. This closes [#12990](https://github.com/ClickHouse/ClickHouse/issues/12990). Updated `rdkafka` to version 1.5 (master). [#12991](https://github.com/ClickHouse/ClickHouse/pull/12991) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix UBSan report in base64 if tests were run on server with AVX-512. This fixes [#12318](https://github.com/ClickHouse/ClickHouse/issues/12318). Author: @qoega. [#12441](https://github.com/ClickHouse/ClickHouse/pull/12441) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix UBSan report in HDFS library. This closes [#12330](https://github.com/ClickHouse/ClickHouse/issues/12330). [#12453](https://github.com/ClickHouse/ClickHouse/pull/12453) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Check an ability that we able to restore the backup from an old version to the new version. This closes [#8979](https://github.com/ClickHouse/ClickHouse/issues/8979). [#12959](https://github.com/ClickHouse/ClickHouse/pull/12959) ([alesapin](https://github.com/alesapin)).
* Do not build helper_container image inside integrational tests. Build docker container in CI and use pre-built helper_container in integration tests. [#12953](https://github.com/ClickHouse/ClickHouse/pull/12953) ([Ilya Yatsishin](https://github.com/qoega)).
* Add a test for `ALTER TABLE CLEAR COLUMN` query for primary key columns. [#12951](https://github.com/ClickHouse/ClickHouse/pull/12951) ([alesapin](https://github.com/alesapin)).
* Increased timeouts in testflows tests. [#12949](https://github.com/ClickHouse/ClickHouse/pull/12949) ([vzakaznikov](https://github.com/vzakaznikov)).
* Fix build of test under Mac OS X. This closes [#12767](https://github.com/ClickHouse/ClickHouse/issues/12767). [#12772](https://github.com/ClickHouse/ClickHouse/pull/12772) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Connector-ODBC updated to mysql-connector-odbc-8.0.21. [#12739](https://github.com/ClickHouse/ClickHouse/pull/12739) ([Ilya Yatsishin](https://github.com/qoega)).
* Adding RBAC syntax tests in TestFlows. [#12642](https://github.com/ClickHouse/ClickHouse/pull/12642) ([vzakaznikov](https://github.com/vzakaznikov)).
* Improve performance of TestKeeper. This will speedup tests with heavy usage of Replicated tables. [#12505](https://github.com/ClickHouse/ClickHouse/pull/12505) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Now we check that server is able to start after stress tests run. This fixes [#12473](https://github.com/ClickHouse/ClickHouse/issues/12473). [#12496](https://github.com/ClickHouse/ClickHouse/pull/12496) ([alesapin](https://github.com/alesapin)).
* Update fmtlib to master (7.0.1). [#12446](https://github.com/ClickHouse/ClickHouse/pull/12446) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add docker image for fast tests. [#12294](https://github.com/ClickHouse/ClickHouse/pull/12294) ([alesapin](https://github.com/alesapin)).
* Rework configuration paths for integration tests. [#12285](https://github.com/ClickHouse/ClickHouse/pull/12285) ([Ilya Yatsishin](https://github.com/qoega)).
* Add compiler option to control that stack frames are not too large. This will help to run the code in fibers with small stack size. [#11524](https://github.com/ClickHouse/ClickHouse/pull/11524) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Update gitignore-files. [#13447](https://github.com/ClickHouse/ClickHouse/pull/13447) ([vladimir-golovchenko](https://github.com/vladimir-golovchenko)).
## ClickHouse release 20.6
### ClickHouse release v20.6.3.28-stable
#### New Feature
* Added an initial implementation of `EXPLAIN` query. Syntax: `EXPLAIN SELECT ...`. This fixes [#1118](https://github.com/ClickHouse/ClickHouse/issues/1118). [#11873](https://github.com/ClickHouse/ClickHouse/pull/11873) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Added storage `RabbitMQ`. [#11069](https://github.com/ClickHouse/ClickHouse/pull/11069) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Implemented PostgreSQL-like `ILIKE` operator for [#11710](https://github.com/ClickHouse/ClickHouse/issues/11710). [#12125](https://github.com/ClickHouse/ClickHouse/pull/12125) ([Mike](https://github.com/myrrc)).
* Supported RIGHT and FULL JOIN with `SET join_algorithm = 'partial_merge'`. Only ALL strictness is allowed (ANY, SEMI, ANTI, ASOF are not). [#12118](https://github.com/ClickHouse/ClickHouse/pull/12118) ([Artem Zuikov](https://github.com/4ertus2)).
* Added a function `initializeAggregation` to initialize an aggregation based on a single value. [#12109](https://github.com/ClickHouse/ClickHouse/pull/12109) ([Guillaume Tassery](https://github.com/YiuRULE)).
* Supported `ALTER TABLE ... [ADD|MODIFY] COLUMN ... FIRST` [#4006](https://github.com/ClickHouse/ClickHouse/issues/4006). [#12073](https://github.com/ClickHouse/ClickHouse/pull/12073) ([Winter Zhang](https://github.com/zhang2014)).
* Added function `parseDateTimeBestEffortUS`. [#12028](https://github.com/ClickHouse/ClickHouse/pull/12028) ([flynn](https://github.com/ucasFL)).
* Support format `ORC` for output (was supported only for input). [#11662](https://github.com/ClickHouse/ClickHouse/pull/11662) ([Kruglov Pavel](https://github.com/Avogar)).
#### Bug Fix
* Fixed `aggregate function any(x) is found inside another aggregate function in query` error with `SET optimize_move_functions_out_of_any = 1` and aliases inside `any()`. [#13419](https://github.com/ClickHouse/ClickHouse/pull/13419) ([Artem Zuikov](https://github.com/4ertus2)).
* Fixed `PrettyCompactMonoBlock` for clickhouse-local. Fixed extremes/totals with `PrettyCompactMonoBlock`. This fixes [#7746](https://github.com/ClickHouse/ClickHouse/issues/7746). [#13394](https://github.com/ClickHouse/ClickHouse/pull/13394) ([Azat Khuzhin](https://github.com/azat)).
* Fixed possible error `Totals having transform was already added to pipeline` in case of a query from delayed replica. [#13290](https://github.com/ClickHouse/ClickHouse/pull/13290) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* The server may crash if user passed specifically crafted arguments to the function `h3ToChildren`. This fixes [#13275](https://github.com/ClickHouse/ClickHouse/issues/13275). [#13277](https://github.com/ClickHouse/ClickHouse/pull/13277) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fixed potentially low performance and slightly incorrect result for `uniqExact`, `topK`, `sumDistinct` and similar aggregate functions called on Float types with NaN values. It also triggered assert in debug build. This fixes [#12491](https://github.com/ClickHouse/ClickHouse/issues/12491). [#13254](https://github.com/ClickHouse/ClickHouse/pull/13254) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fixed function if with nullable constexpr as cond that is not literal NULL. Fixes [#12463](https://github.com/ClickHouse/ClickHouse/issues/12463). [#13226](https://github.com/ClickHouse/ClickHouse/pull/13226) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fixed assert in `arrayElement` function in case of array elements are Nullable and array subscript is also Nullable. This fixes [#12172](https://github.com/ClickHouse/ClickHouse/issues/12172). [#13224](https://github.com/ClickHouse/ClickHouse/pull/13224) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fixed `DateTime64` conversion functions with constant argument. [#13205](https://github.com/ClickHouse/ClickHouse/pull/13205) ([Azat Khuzhin](https://github.com/azat)).
* Fixed wrong index analysis with functions. It could lead to pruning wrong parts, while reading from `MergeTree` tables. Fixes [#13060](https://github.com/ClickHouse/ClickHouse/issues/13060). Fixes [#12406](https://github.com/ClickHouse/ClickHouse/issues/12406). [#13081](https://github.com/ClickHouse/ClickHouse/pull/13081) ([Anton Popov](https://github.com/CurtizJ)).
* Fixed error `Cannot convert column because it is constant but values of constants are different in source and result` for remote queries which use deterministic functions in scope of query, but not deterministic between queries, like `now()`, `now64()`, `randConstant()`. Fixes [#11327](https://github.com/ClickHouse/ClickHouse/issues/11327). [#13075](https://github.com/ClickHouse/ClickHouse/pull/13075) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fixed unnecessary limiting for the number of threads for selects from local replica. [#12840](https://github.com/ClickHouse/ClickHouse/pull/12840) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fixed rare bug when `ALTER DELETE` and `ALTER MODIFY COLUMN` queries executed simultaneously as a single mutation. Bug leads to an incorrect amount of rows in `count.txt` and as a consequence incorrect data in part. Also, fix a small bug with simultaneous `ALTER RENAME COLUMN` and `ALTER ADD COLUMN`. [#12760](https://github.com/ClickHouse/ClickHouse/pull/12760) ([alesapin](https://github.com/alesapin)).
* Fixed `CAST(Nullable(String), Enum())`. [#12745](https://github.com/ClickHouse/ClickHouse/pull/12745) ([Azat Khuzhin](https://github.com/azat)).
* Fixed a performance with large tuples, which are interpreted as functions in `IN` section. The case when user write `WHERE x IN tuple(1, 2, ...)` instead of `WHERE x IN (1, 2, ...)` for some obscure reason. [#12700](https://github.com/ClickHouse/ClickHouse/pull/12700) ([Anton Popov](https://github.com/CurtizJ)).
* Fixed memory tracking for `input_format_parallel_parsing` (by attaching thread to group). [#12672](https://github.com/ClickHouse/ClickHouse/pull/12672) ([Azat Khuzhin](https://github.com/azat)).
* Fixed bloom filter index with const expression. This fixes [#10572](https://github.com/ClickHouse/ClickHouse/issues/10572). [#12659](https://github.com/ClickHouse/ClickHouse/pull/12659) ([Winter Zhang](https://github.com/zhang2014)).
* Fixed `SIGSEGV` in `StorageKafka` when broker is unavailable (and not only). [#12658](https://github.com/ClickHouse/ClickHouse/pull/12658) ([Azat Khuzhin](https://github.com/azat)).
* Added support for function `if` with `Array(UUID)` arguments. This fixes [#11066](https://github.com/ClickHouse/ClickHouse/issues/11066). [#12648](https://github.com/ClickHouse/ClickHouse/pull/12648) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* `CREATE USER IF NOT EXISTS` now doesn't throw exception if the user exists. This fixes [#12507](https://github.com/ClickHouse/ClickHouse/issues/12507). [#12646](https://github.com/ClickHouse/ClickHouse/pull/12646) ([Vitaly Baranov](https://github.com/vitlibar)).
* Better exception message in disk access storage. [#12625](https://github.com/ClickHouse/ClickHouse/pull/12625) ([alesapin](https://github.com/alesapin)).
* The function `groupArrayMoving*` was not working for distributed queries. It's result was calculated within incorrect data type (without promotion to the largest type). The function `groupArrayMovingAvg` was returning integer number that was inconsistent with the `avg` function. This fixes [#12568](https://github.com/ClickHouse/ClickHouse/issues/12568). [#12622](https://github.com/ClickHouse/ClickHouse/pull/12622) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fixed lack of aliases with function `any`. [#12593](https://github.com/ClickHouse/ClickHouse/pull/12593) ([Anton Popov](https://github.com/CurtizJ)).
* Fixed race condition in external dictionaries with cache layout which can lead server crash. [#12566](https://github.com/ClickHouse/ClickHouse/pull/12566) ([alesapin](https://github.com/alesapin)).
* Remove data for Distributed tables (blocks from async INSERTs) on DROP TABLE. [#12556](https://github.com/ClickHouse/ClickHouse/pull/12556) ([Azat Khuzhin](https://github.com/azat)).
* Fixed bug which lead to broken old parts after `ALTER DELETE` query when `enable_mixed_granularity_parts=1`. Fixes [#12536](https://github.com/ClickHouse/ClickHouse/issues/12536). [#12543](https://github.com/ClickHouse/ClickHouse/pull/12543) ([alesapin](https://github.com/alesapin)).
* Better exception for function `in` with invalid number of arguments. [#12529](https://github.com/ClickHouse/ClickHouse/pull/12529) ([Anton Popov](https://github.com/CurtizJ)).
* Fixing race condition in live view tables which could cause data duplication. [#12519](https://github.com/ClickHouse/ClickHouse/pull/12519) ([vzakaznikov](https://github.com/vzakaznikov)).
* Fixed performance issue, while reading from compact parts. [#12492](https://github.com/ClickHouse/ClickHouse/pull/12492) ([Anton Popov](https://github.com/CurtizJ)).
* Fixed backwards compatibility in binary format of `AggregateFunction(avg, ...)` values. This fixes [#12342](https://github.com/ClickHouse/ClickHouse/issues/12342). [#12486](https://github.com/ClickHouse/ClickHouse/pull/12486) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fixed SETTINGS parse after FORMAT. [#12480](https://github.com/ClickHouse/ClickHouse/pull/12480) ([Azat Khuzhin](https://github.com/azat)).
* Fixed the deadlock if `text_log` is enabled. [#12452](https://github.com/ClickHouse/ClickHouse/pull/12452) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fixed overflow when very large `LIMIT` or `OFFSET` is specified. This fixes [#10470](https://github.com/ClickHouse/ClickHouse/issues/10470). This fixes [#11372](https://github.com/ClickHouse/ClickHouse/issues/11372). [#12427](https://github.com/ClickHouse/ClickHouse/pull/12427) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fixed possible segfault if `StorageMerge`. This fixes [#12054](https://github.com/ClickHouse/ClickHouse/issues/12054). [#12401](https://github.com/ClickHouse/ClickHouse/pull/12401) ([tavplubix](https://github.com/tavplubix)).
* Reverted change introduced in [#11079](https://github.com/ClickHouse/ClickHouse/issues/11079) to resolve [#12098](https://github.com/ClickHouse/ClickHouse/issues/12098). [#12397](https://github.com/ClickHouse/ClickHouse/pull/12397) ([Mike](https://github.com/myrrc)).