From 061a1cae31e08f06283abf53195717aba0c307c8 Mon Sep 17 00:00:00 2001
From: Gail Badner <gbadner@redhat.com>
Date: Fri, 12 May 2017 13:49:29 -0700
Subject: [PATCH] HHH-11740 : Default MultiTableBulkIdStrategy for DB2 does not
 work with connection pools

---
 .../org/hibernate/dialect/DB297Dialect.java   | 31 +++++++++++++++++++
 .../org/hibernate/dialect/DB2Dialect.java     |  9 ++++--
 2 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/hibernate-core/src/main/java/org/hibernate/dialect/DB297Dialect.java b/hibernate-core/src/main/java/org/hibernate/dialect/DB297Dialect.java
index 7715c6293319..fd80bc4eeb2b 100644
--- a/hibernate-core/src/main/java/org/hibernate/dialect/DB297Dialect.java
+++ b/hibernate-core/src/main/java/org/hibernate/dialect/DB297Dialect.java
@@ -6,6 +6,12 @@
  */
 package org.hibernate.dialect;
 
+import org.hibernate.hql.spi.id.IdTableSupportStandardImpl;
+import org.hibernate.hql.spi.id.MultiTableBulkIdStrategy;
+import org.hibernate.hql.spi.id.global.GlobalTemporaryTableBulkIdStrategy;
+import org.hibernate.hql.spi.id.local.AfterUseAction;
+import org.hibernate.hql.spi.id.local.LocalTemporaryTableBulkIdStrategy;
+
 /**
  * An SQL dialect for DB2 9.7.
  *
@@ -18,4 +24,29 @@ public String getCrossJoinSeparator() {
 		// DB2 9.7 and later support "cross join"
 		return " cross join ";
 	}
+
+	@Override
+	public MultiTableBulkIdStrategy getDefaultMultiTableBulkIdStrategy() {
+		// Starting in DB2 9.7, "real" global temporary tables that can be shared between sessions
+		// are supported; (obviously) data is not shared between sessions.
+		return new GlobalTemporaryTableBulkIdStrategy(
+				new IdTableSupportStandardImpl() {
+					@Override
+					public String generateIdTableName(String baseName) {
+						return super.generateIdTableName( baseName );
+					}
+
+					@Override
+					public String getCreateIdTableCommand() {
+						return "create global temporary table";
+					}
+
+					@Override
+					public String getCreateIdTableStatementOptions() {
+						return "not logged";
+					}
+				},
+				AfterUseAction.CLEAN
+		);
+	}
 }
diff --git a/hibernate-core/src/main/java/org/hibernate/dialect/DB2Dialect.java b/hibernate-core/src/main/java/org/hibernate/dialect/DB2Dialect.java
index cf0a883e4aa4..7e3ea78b576d 100644
--- a/hibernate-core/src/main/java/org/hibernate/dialect/DB2Dialect.java
+++ b/hibernate-core/src/main/java/org/hibernate/dialect/DB2Dialect.java
@@ -35,6 +35,7 @@
 import org.hibernate.hql.spi.id.MultiTableBulkIdStrategy;
 import org.hibernate.hql.spi.id.global.GlobalTemporaryTableBulkIdStrategy;
 import org.hibernate.hql.spi.id.local.AfterUseAction;
+import org.hibernate.hql.spi.id.local.LocalTemporaryTableBulkIdStrategy;
 import org.hibernate.internal.CoreLogging;
 import org.hibernate.internal.CoreMessageLogger;
 import org.hibernate.internal.util.JdbcExceptionHelper;
@@ -379,7 +380,10 @@ public boolean supportsCommentOn() {
 
 	@Override
 	public MultiTableBulkIdStrategy getDefaultMultiTableBulkIdStrategy() {
-		return new GlobalTemporaryTableBulkIdStrategy(
+		// Prior to DB2 9.7, "real" global temporary tables that can be shared between sessions
+		// are *not* supported; even though the DB2 command says to declare a "global" temp table
+		// Hibernate treats it as a "local" temp table.
+		return new LocalTemporaryTableBulkIdStrategy(
 				new IdTableSupportStandardImpl() {
 					@Override
 					public String generateIdTableName(String baseName) {
@@ -396,7 +400,8 @@ public String getCreateIdTableStatementOptions() {
 						return "not logged";
 					}
 				},
-				AfterUseAction.CLEAN
+				AfterUseAction.DROP,
+				null
 		);
 	}