[jira] Assigned: (DERBY-808) PreparedStatements can take longer to execute than Statements. There seem to be a problem with searchClauseTransitiveClosure method in PredicateList.java

["Rajesh Kartha (JIRA)" <de...@db.apache.org>]

     [ http://issues.apache.org/jira/browse/DERBY-808?page=all ]

Rajesh Kartha reassigned DERBY-808:
-----------------------------------

    Assign To: Rajesh Kartha

> 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: 10.1.2.0, 10.2.0.0
>  Environment: generic
>     Reporter: Satheesh Bandaram
>     Assignee: Rajesh Kartha
>      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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