You are viewing a plain text version of this content. The canonical link for it is here.
Posted to derby-dev@db.apache.org by "Mike Matrigali (JIRA)" <ji...@apache.org> on 2013/06/19 19:22:21 UTC
[jira] [Closed] (DERBY-2699) performance of like in territory based
collation databases may be improved by changing way collation elements are
calculated.
[ https://issues.apache.org/jira/browse/DERBY-2699?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Mike Matrigali closed DERBY-2699.
---------------------------------
> performance of like in territory based collation databases may be improved by changing way collation elements are calculated.
> -----------------------------------------------------------------------------------------------------------------------------
>
> Key: DERBY-2699
> URL: https://issues.apache.org/jira/browse/DERBY-2699
> Project: Derby
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 10.3.1.4
> Reporter: Mike Matrigali
> Assignee: Knut Anders Hatlen
> Labels: derby_triage10_10
> Fix For: 10.10.1.1
>
> Attachments: d2699-1a.diff
>
>
> WorkHorseForCollatorDatatypes.java has a method getCollationElementsForString() which currently gets
> called when processing like clauses in databases that have been created with territory based collation, this is
> not an issue in pre-10.3 databases or post 10.3 default databases.
> getCollationElementsForString gets the collation elements for the entire value of the String held by
> the datatype using the class.
> If you take the case of pattern 'A%' and the value of datatype is 'BXXXXXXXXXXXXXXXXXXXXXXX',
> then it would have been better to better to get collation elements one character of the String value at a time
> to avoid the process of getting collation elements for the entire string when we don't really need it
> One could imagine this might have a huge performance impact on running like against a long clob where
> the like pattern has leading fixed-length pattern to match.
> Comments on this from Dan and Dag can be found in DERBY-2416.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira