From 27ca78eafc10aa8bebedac496624a6414d33209b Mon Sep 17 00:00:00 2001 From: Felipe Gasper Date: Thu, 28 Sep 2023 12:58:48 -0400 Subject: [PATCH 1/2] Update the README for known issues & limitations. --- README.md | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/README.md b/README.md index be98d961..85e147b0 100644 --- a/README.md +++ b/README.md @@ -94,10 +94,6 @@ The verifier will now check to completion to make sure that there are no inconsi `{"progress":{"phase":"idle","error":null,"verificationStatus":{"totalTasks":1,"addedTasks":0,"processingTasks":0,"failedTasks":1,"completedTasks":0,"metadataMismatchTasks":0,"recheckTasks":0}}}` -# Limitation - -The verifier’s iterative process can handle data changes while it is running, until you hit the writesOff endpoint. However, it cannot handle DDL commands. If the verifier receives a DDL change stream event (drop, dropDatabase, rename), the verification will fail. If an untracked DDL event (create, createIndexes, dropIndexes, modify) occurs, the verifier may miss the change. - # Benchmarking Results Ran on m6id.metal + M40 with 3 replica sets @@ -220,3 +216,15 @@ Any collection metadata mismatches will occur in a task with the type '`verifyCo In this case, '`failed_docs`' contains all the meta data mismatches, in this case an index named '`x_1`'. + +# Known Problems + +- The verifier may report missing documents on the destination that don’t actually appear to be missing (i.e., a nonexistent problem). This has been hard to reproduce. + +- The verifier, during its first generation, may report a confusing “Mismatches found” but then report 0 problems. This is a reporting bug in mongosync; if you see it, check the documents in `migration_verification_metadata.verification_tasks` for generation 1 (not generation 0). + +# Limitations + +- The verifier’s iterative process can handle data changes while it is running, until you hit the writesOff endpoint. However, it cannot handle DDL commands. If the verifier receives a DDL change stream event (drop, dropDatabase, rename), the verification will fail. If an untracked DDL event (create, createIndexes, dropIndexes, modify) occurs, the verifier may miss the change. + +- The verifier crashes if it tries to compare time-series collections. The error will include a phrase like “Collection has nil UUID (most probably is a view)” and also mention “timeseries”. From 03e2cff1540db96ef7793b732998c88d435fbd9e Mon Sep 17 00:00:00 2001 From: Tim Fogarty Date: Thu, 28 Sep 2023 13:54:17 -0400 Subject: [PATCH 2/2] Update README.md --- README.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/README.md b/README.md index 85e147b0..d4f54716 100644 --- a/README.md +++ b/README.md @@ -217,9 +217,9 @@ Any collection metadata mismatches will occur in a task with the type '`verifyCo In this case, '`failed_docs`' contains all the meta data mismatches, in this case an index named '`x_1`'. -# Known Problems +# Known Issues -- The verifier may report missing documents on the destination that don’t actually appear to be missing (i.e., a nonexistent problem). This has been hard to reproduce. +- The verifier may report missing documents on the destination that don’t actually appear to be missing (i.e., a nonexistent problem). This has been hard to reproduce. If missing documents are reported, it is good practice to check for false positives. - The verifier, during its first generation, may report a confusing “Mismatches found” but then report 0 problems. This is a reporting bug in mongosync; if you see it, check the documents in `migration_verification_metadata.verification_tasks` for generation 1 (not generation 0).