[jira] [Resolved] (CALCITE-2619) Reduce string literal creation cost by removing unnecessary charset check

["Julian Hyde (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CALCITE-2619?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Julian Hyde resolved CALCITE-2619.
----------------------------------
       Resolution: Fixed
    Fix Version/s: 1.18.0

Fixed in [36bd5fb2|http://git-wip-us.apache.org/repos/asf/calcite/commit/36bd5fb2]; thanks for the PR, [~tedxu]!

I made some changes to your PR. I changed the two public NlsString constructors to use the same private constructor, made all fields final (so NlsString is now immutable), and obsoleted your ByteString class, using instead a pair of Avatica's ByteString and a Charset in the cache. (Your ByteString had a charset, while Avatica's ByteString only has an array of bytes.) Lastly, I made your cache static; a non-static cache would have been useless.

> Reduce string literal creation cost by removing unnecessary 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
>             Fix For: 1.18.0
>
>
> 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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