Set Hibernate ORM connection handling strategy to BEFORE_TRANSACTION_…

…COMPLETION

extensions/hibernate-orm/runtime/src/main/java/io/quarkus/hibernate/orm/runtime/boot/FastBootMetadataBuilder.java

@@ -64,6 +64,7 @@
 import org.hibernate.jpa.internal.util.LogHelper;
 import org.hibernate.jpa.internal.util.PersistenceUnitTransactionTypeHelper;
 import org.hibernate.jpa.spi.IdentifierGeneratorStrategyProvider;
+import org.hibernate.resource.jdbc.spi.PhysicalConnectionHandlingMode;
 import org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorBuilderImpl;
 import org.hibernate.resource.transaction.backend.jta.internal.JtaTransactionCoordinatorBuilderImpl;
 import org.hibernate.service.Service;
@@ -241,6 +242,21 @@ private MergedSettings mergeSettings(PersistenceUnitDescriptor persistenceUnit)
         //Agroal already does disable auto-commit, so Hibernate ORM should trust that:
         cfg.put(AvailableSettings.CONNECTION_PROVIDER_DISABLES_AUTOCOMMIT, Boolean.TRUE.toString());
 
+        /**
+         * Set CONNECTION_HANDLING to DELAYED_ACQUISITION_AND_RELEASE_BEFORE_TRANSACTION_COMPLETION
+         * as it generally performs better, at no known drawbacks.
+         * This is a new mode in Hibernate ORM, it might become the default in the future.
+         *
+         * @see org.hibernate.resource.jdbc.spi.PhysicalConnectionHandlingMode
+         */
+        {
+            final Object explicitSetting = cfg.get(AvailableSettings.CONNECTION_HANDLING);
+            if (explicitSetting == null) {
+                cfg.put(AvailableSettings.CONNECTION_HANDLING,
+                        PhysicalConnectionHandlingMode.DELAYED_ACQUISITION_AND_RELEASE_BEFORE_TRANSACTION_COMPLETION);
+            }
+        }
+
         if (readBooleanConfigurationValue(cfg, WRAP_RESULT_SETS)) {
             LOG.warn("Wrapping result sets is not supported. Setting " + WRAP_RESULT_SETS + " to false.");
         }