[ http://issues.apache.org/jira/browse/DERBY-808?page=comments#action_12363074 ]
Daniel John Debrunner commented on DERBY-808: --------------------------------------------- Good find, I'd never thought that Statements could be slower than PreparedStatements. + // Consider using variant type of the expression, instead of ConstantNode + // or ParameterNode while porting this fix to trunk. I would advise porting this fix as-is to the trunk to avoid people hitting similar problems there, and enter a new jira issue for possibly improving it as you describe. > PreparedStatements can take longer to execute than Statements. There seem to > be a problem with searchClauseTransitiveClosure method in PredicateList.java > --------------------------------------------------------------------------------------------------------------------------------------------------------- > > Key: DERBY-808 > URL: http://issues.apache.org/jira/browse/DERBY-808 > Project: Derby > Type: Bug > Components: SQL > Versions: 10.2.0.0, 10.1.2.0 > Environment: generic > Reporter: Satheesh Bandaram > Fix For: 10.2.0.0, 10.1.3.0 > Attachments: DERBY-808.patch > > PreparedStatements could take much longer than Statements because of > incorrect search clause transitive closure optimization. For the customer > case I investigated this problem, Statement would complete in about 13 > seconds, where as equivalent PreparedStatement ran "forever". (stoped it > after hours) > I think there a problem with PredicateList.searchClauseTransitiveClosure > method. This method tries to add new search clauses based on equality join > between tables involved. Current code only looks for ConstantNodes on the > right side of searchClauses. This would miss ParameterNodes, so Derby might > miss search clause transitive closure optimizations for PreparedStatements. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira
