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https://issues.apache.org/jira/browse/DERBY-1879?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Dag H. Wanvik updated DERBY-1879:
---------------------------------

    Derby Categories: [Performance]

> Save meta data related information for an EmbedResultSet at the plan level 
> instead of the ResultSet level improves performance.
> -------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: DERBY-1879
>                 URL: https://issues.apache.org/jira/browse/DERBY-1879
>             Project: Derby
>          Issue Type: Improvement
>          Components: JDBC
>            Reporter: Daniel John Debrunner
>            Assignee: Daniel John Debrunner
>            Priority: Minor
>             Fix For: 10.3.1.4
>
>         Attachments: derby1879_diff.txt
>
>
> EmbedResultSet creates and holds references to information that logically is 
> at the plan level, the same for all ResultSet's that use the same prepared 
> plan. Holding this information at the EmbedResultSet hurts performance and 
> memory usage as ResultSet objects are short lived.
> Saving the ResultSetMetaData object in the ResultDescription object means a 
> single creation for the lifetime of the plan (shared across connections), 
> rather than once per ResultSet object as needed.
> Saving the column name to position mapping added in DERBY-1862 in the 
> ResultDescription has a similar benefit, the map is set up once per prepared 
> plan, not once per executeQuery().
> With test changes (will attach patch soon), the performance of the derby1862 
> test in DERBY-1876 improves by around 15%

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