[jira] Updated: (DERBY-818) Read-only embedded ResultSets incur performance penalty due to updateable ResultSet code.

["Daniel John Debrunner (JIRA)" <de...@db.apache.org>]

     [ http://issues.apache.org/jira/browse/DERBY-818?page=all ]

Daniel John Debrunner updated DERBY-818:
----------------------------------------

    Attachment: derby818patch.txt

This patch addresses the issue by:
1) Only allocating the arrays if the ResultSet is updateable
2) Only reseting the arrays in next() if they  have been allocated
3) Using Arrays.fill() to reset the array.
4) Removing the reset of the arrays from the close() method, I can't see any logic for placing it there.

I'd appreciate anyone who has worked on updateable result sets looking at the patch.

I'm re-running derbyall to ensure no failures with the patch.


> Read-only embedded ResultSets incur performance penalty due to updateable ResultSet code.
> -----------------------------------------------------------------------------------------
>
>          Key: DERBY-818
>          URL: http://issues.apache.org/jira/browse/DERBY-818
>      Project: Derby
>         Type: Improvement
>   Components: JDBC, Performance
>     Reporter: Daniel John Debrunner
>     Assignee: Daniel John Debrunner
>     Priority: Minor
>  Attachments: derby818patch.txt
>
> The fields columnGotUpdated and copyOfDatabaseRow are allocated and maintained in EmbedResultSet for every ResultSet but they are only required if the result set is updateable. I saw a 5% improvement in execution rate on a simple VALUES clause when fixing this.

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