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Posted to issues@calcite.apache.org by "Julian Hyde (JIRA)" <ji...@apache.org> on 2018/10/11 05:46:00 UTC
[jira] [Commented] (CALCITE-2619) Reduce string literal creation
cost by removing charset check
[ https://issues.apache.org/jira/browse/CALCITE-2619?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16645996#comment-16645996 ]
Julian Hyde commented on CALCITE-2619:
--------------------------------------
I think the charset test is useful. Is there any way we can amortize its cost, eg caching the charset after it has been looked up, or using a special path for easy, common charsets, or short-cutting validation when a NlsString is copied?
> Reduce string literal creation cost by removing charset check
> -------------------------------------------------------------
>
> Key: CALCITE-2619
> URL: https://issues.apache.org/jira/browse/CALCITE-2619
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Reporter: Ted Xu
> Assignee: Julian Hyde
> Priority: Major
>
> The cost of creating NlsString is very high, due to its charset check. In some cases, e.g., expression evaluate because of Partition Prune, the NlsString creation costs 40%+ of total executor's overhead.
>
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