[ http://issues.apache.org/jira/browse/DERBY-808?page=all ]
Satheesh Bandaram updated DERBY-808:
------------------------------------
Summary: PreparedStatements can take longer to execute than equivalent
Statements when there are multiple join conditions mixed with some search
clauses. (was: PreparedStatements can take longer to execute than Statements.
There seem to be a problem with searchClauseTransitiveClosure method in
PredicateList.java)
> PreparedStatements can take longer to execute than equivalent Statements when
> there are multiple join conditions mixed with some search clauses.
> ------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: DERBY-808
> URL: http://issues.apache.org/jira/browse/DERBY-808
> Project: Derby
> Type: Bug
> Components: SQL
> Versions: 10.1.2.0, 10.2.0.0
> Environment: generic
> Reporter: Satheesh Bandaram
> Assignee: Satheesh Bandaram
> Fix For: 10.2.0.0, 10.1.3.0, 10.1.2.2
> 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.
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