From 7a2345f8ff7518891533c9000e23c21602fdc690 Mon Sep 17 00:00:00 2001
From: Gavin King <gavin@hibernate.org>
Date: Thu, 16 Jan 2025 22:53:42 +0100
Subject: [PATCH] possible mitigation for Oracle fetch size issue
---
.../ExtractedDatabaseMetaDataImpl.java | 18 +++++++++++++++++-
.../jdbc/env/internal/JdbcEnvironmentImpl.java | 15 +++++++++++++++
.../env/spi/ExtractedDatabaseMetaData.java | 5 +++++
3 files changed, 37 insertions(+), 1 deletion(-)
diff --git a/hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/internal/ExtractedDatabaseMetaDataImpl.java b/hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/internal/ExtractedDatabaseMetaDataImpl.java
index 09357e475eca..48b4e1baecd7 100644
--- a/hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/internal/ExtractedDatabaseMetaDataImpl.java
+++ b/hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/internal/ExtractedDatabaseMetaDataImpl.java
@@ -8,6 +8,7 @@
import java.sql.DatabaseMetaData;
import java.sql.ResultSet;
import java.sql.SQLException;
+import java.sql.Statement;
import java.util.Collections;
import java.util.List;
import java.util.stream.Collectors;
@@ -49,7 +50,7 @@ public class ExtractedDatabaseMetaDataImpl implements ExtractedDatabaseMetaData
private final String url;
private final String driver;
private final boolean jdbcMetadataAccessible;
-
+ private final int defaultFetchSize;
//Lazily initialized: loading all sequence information upfront has been
//shown to be too slow in some cases. In this way we only load it
@@ -71,6 +72,7 @@ private ExtractedDatabaseMetaDataImpl(
SQLStateType sqlStateType,
int transactionIsolation,
int defaultTransactionIsolation,
+ int defaultFetchSize,
String url,
String driver,
boolean jdbcMetadataIsAccessible) {
@@ -88,6 +90,7 @@ private ExtractedDatabaseMetaDataImpl(
this.sqlStateType = sqlStateType;
this.transactionIsolation = transactionIsolation;
this.defaultTransactionIsolation = defaultTransactionIsolation;
+ this.defaultFetchSize = defaultFetchSize;
this.url = url;
this.driver = driver;
this.jdbcMetadataAccessible = jdbcMetadataIsAccessible;
@@ -168,6 +171,11 @@ public int getDefaultTransactionIsolation() {
return defaultTransactionIsolation;
}
+ @Override
+ public int getDefaultFetchSize() {
+ return defaultFetchSize;
+ }
+
@Override
public synchronized List<SequenceInformation> getSequenceInformationList() {
if ( jdbcMetadataAccessible ) {
@@ -211,6 +219,7 @@ public static class Builder {
private String driver;
private int defaultTransactionIsolation;
private int transactionIsolation;
+ private int defaultFetchSize;
public Builder(JdbcEnvironment jdbcEnvironment, boolean jdbcMetadataIsAccessible, JdbcConnectionAccess connectionAccess) {
this.jdbcEnvironment = jdbcEnvironment;
@@ -233,6 +242,12 @@ public Builder apply(DatabaseMetaData databaseMetaData) throws SQLException {
driver = databaseMetaData.getDriverName();
defaultTransactionIsolation = databaseMetaData.getDefaultTransactionIsolation();
transactionIsolation = databaseMetaData.getConnection().getTransactionIsolation();
+ try ( Statement statement = databaseMetaData.getConnection().createStatement() ) {
+ defaultFetchSize = statement.getFetchSize();
+ }
+ catch (SQLException sqle) {
+ defaultFetchSize = -1;
+ }
return this;
}
@@ -302,6 +317,7 @@ public ExtractedDatabaseMetaDataImpl build() {
sqlStateType,
transactionIsolation,
defaultTransactionIsolation,
+ defaultFetchSize,
url,
driver,
jdbcMetadataIsAccessible
diff --git a/hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/internal/JdbcEnvironmentImpl.java b/hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/internal/JdbcEnvironmentImpl.java
index e75275618073..6e6d3ee6c6f7 100644
--- a/hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/internal/JdbcEnvironmentImpl.java
+++ b/hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/internal/JdbcEnvironmentImpl.java
@@ -10,6 +10,7 @@
import org.hibernate.boot.model.naming.Identifier;
import org.hibernate.boot.registry.selector.spi.StrategySelector;
import org.hibernate.cfg.AvailableSettings;
+import org.hibernate.cfg.JdbcSettings;
import org.hibernate.dialect.Dialect;
import org.hibernate.engine.config.spi.ConfigurationService;
import org.hibernate.engine.config.spi.StandardConverters;
@@ -103,6 +104,8 @@ public JdbcEnvironmentImpl(final ServiceRegistryImplementor serviceRegistry, fin
this.qualifiedObjectNameFormatter = new QualifiedObjectNameFormatterStandardImpl( nameQualifierSupport );
this.lobCreatorBuilder = makeLobCreatorBuilder( dialect );
+
+ logJdbcFetchSize( extractedMetaDataSupport.getDefaultFetchSize(), cfgService );
}
private IdentifierHelperBuilder identifierHelperBuilder(
@@ -312,6 +315,8 @@ public JdbcEnvironmentImpl(
cfgService.getSettings(),
databaseMetaData.getConnection()
);
+
+ logJdbcFetchSize( extractedMetaDataSupport.getDefaultFetchSize(), cfgService );
}
private static IdentifierHelper identifierHelper(
@@ -420,4 +425,14 @@ public LobCreatorBuilder getLobCreatorBuilder() {
return lobCreatorBuilder;
}
+ private static void logJdbcFetchSize(int defaultFetchSize, ConfigurationService cfgService) {
+ if ( !cfgService.getSettings().containsKey( JdbcSettings.STATEMENT_FETCH_SIZE ) ) {
+ if ( defaultFetchSize > 0 && defaultFetchSize < 200 ) {
+ log.warn( "Low default JDBC fetch size: " + defaultFetchSize + " (set hibernate.jdbc.fetch_size)" );
+ }
+ else {
+ log.debug( "Using default JDBC fetch size: " + defaultFetchSize );
+ }
+ }
+ }
}
diff --git a/hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/spi/ExtractedDatabaseMetaData.java b/hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/spi/ExtractedDatabaseMetaData.java
index 48182669e367..0bfb244ee5c1 100644
--- a/hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/spi/ExtractedDatabaseMetaData.java
+++ b/hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/spi/ExtractedDatabaseMetaData.java
@@ -150,6 +150,11 @@ public interface ExtractedDatabaseMetaData {
*/
int getDefaultTransactionIsolation();
+ /**
+ * Retrieve the default JDBC {@link java.sql.Statement#getFetchSize fetch size}.
+ */
+ int getDefaultFetchSize();
+
/**
* Retrieve the list of {@code SequenceInformation} objects which describe the underlying database sequences.
*