HHH-7840 org.hibernate.id.IncrementGenerator very slow

brmeyer · brmeyer · commit 263a84154e97 · 2012-12-07T11:16:48.000-05:00
diff --git a/hibernate-core/src/main/java/org/hibernate/id/IncrementGenerator.java b/hibernate-core/src/main/java/org/hibernate/id/IncrementGenerator.java
@@ -53,6 +53,7 @@
  *
  * @author Gavin King
  * @author Steve Ebersole
+ * @author Brett Meyer
  */
 public class IncrementGenerator implements IdentifierGenerator, Configurable {
 
@@ -103,7 +104,7 @@ public void configure(Type type, Properties params, Dialect dialect) throws Mapp
 		for ( int i=0; i < tables.length; i++ ) {
 			final String tableName = dialect.quote( normalizer.normalizeIdentifierQuoting( tables[i] ) );
 			if ( tables.length > 1 ) {
-				buf.append( "select " ).append( column ).append( " from " );
+				buf.append( "select max(" ).append( column ).append( ") as mx from " );
 			}
 			buf.append( Table.qualify( catalog, schema, tableName ) );
 			if ( i < tables.length-1 ) {
@@ -112,7 +113,7 @@ public void configure(Type type, Properties params, Dialect dialect) throws Mapp
 		}
 		if ( tables.length > 1 ) {
 			buf.insert( 0, "( " ).append( " ) ids_" );
-			column = "ids_." + column;
+			column = "ids_.mx";
 		}
 
 		sql = "select max(" + column + ") from " + buf.toString();

Original file line number	Diff line number	Diff line change
`@@ -53,6 +53,7 @@`
`53`	`53`	`*`
`54`	`54`	`* @author Gavin King`
`55`	`55`	`* @author Steve Ebersole`
	`56`	`+ * @author Brett Meyer`
`56`	`57`	`*/`
`57`	`58`	`public class IncrementGenerator implements IdentifierGenerator, Configurable {`
`58`	`59`
`@@ -103,7 +104,7 @@ public void configure(Type type, Properties params, Dialect dialect) throws Mapp`
`103`	`104`	`for ( int i=0; i < tables.length; i++ ) {`
`104`	`105`	`final String tableName = dialect.quote( normalizer.normalizeIdentifierQuoting( tables[i] ) );`
`105`	`106`	`if ( tables.length > 1 ) {`
`106`		`- buf.append( "select " ).append( column ).append( " from " );`
	`107`	`+ buf.append( "select max(" ).append( column ).append( ") as mx from " );`
`107`	`108`	`}`
`108`	`109`	`buf.append( Table.qualify( catalog, schema, tableName ) );`
`109`	`110`	`if ( i < tables.length-1 ) {`
`@@ -112,7 +113,7 @@ public void configure(Type type, Properties params, Dialect dialect) throws Mapp`
`112`	`113`	`}`
`113`	`114`	`if ( tables.length > 1 ) {`
`114`	`115`	`buf.insert( 0, "( " ).append( " ) ids_" );`
`115`		`- column = "ids_." + column;`
	`116`	`+ column = "ids_.mx";`
`116`	`117`	`}`
`117`	`118`
`118`	`119`	`sql = "select max(" + column + ") from " + buf.toString();`