HHH-8939 Reduce contention on initialization of ColumnNameCache insta…

…nces by loaders
hibernate · Feb 18, 2014 · 0c5c980 · 0c5c980
1 parent 09ea1b3
commit 0c5c980
Showing 1 changed file with 10 additions and 8 deletions.
diff --git a/hibernate-core/src/main/java/org/hibernate/loader/Loader.java b/hibernate-core/src/main/java/org/hibernate/loader/Loader.java
@@ -2101,15 +2101,17 @@ private ResultSet wrapResultSetIfEnabled(final ResultSet rs, final SessionImplem
 	}
 
 	private ColumnNameCache retreiveColumnNameToIndexCache(final ResultSet rs) throws SQLException {
-		if ( columnNameCache == null ) {
-			synchronized ( this ) {
-				if ( columnNameCache == null ) {
-					LOG.trace( "Building columnName -> columnIndex cache" );
-					columnNameCache = new ColumnNameCache( rs.getMetaData().getColumnCount() );
-				}
-			}
+		final ColumnNameCache cache = columnNameCache;
+		if ( cache == null ) {
+			//there is no need for a synchronized second check, as in worst case
+			//we'll have allocated an unnecessary ColumnNameCache
+			LOG.trace( "Building columnName -> columnIndex cache" );
+			columnNameCache = new ColumnNameCache( rs.getMetaData().getColumnCount() );
+			return columnNameCache;
+		}
+		else {
+			return cache;
 		}
-		return columnNameCache;
 	}
 
 	/**