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Posted to issues@kudu.apache.org by "Todd Lipcon (JIRA)" <ji...@apache.org> on 2017/03/23 18:49:41 UTC
[jira] [Resolved] (KUDU-1712) Schema::EncodeComparableKey burns CPU
in compaction
[ https://issues.apache.org/jira/browse/KUDU-1712?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Todd Lipcon resolved KUDU-1712.
-------------------------------
Resolution: Fixed
Fix Version/s: 1.4.0
After the above, this is farther down the profile, probably not high priority to address anymore unless it bubbles back up towards the top in a particular workload
> Schema::EncodeComparableKey burns CPU in compaction
> ---------------------------------------------------
>
> Key: KUDU-1712
> URL: https://issues.apache.org/jira/browse/KUDU-1712
> Project: Kudu
> Issue Type: Bug
> Components: perf, tablet
> Affects Versions: 1.0.1
> Reporter: Todd Lipcon
> Fix For: 1.4.0
>
>
> Looking at a workload that is CPU-bound in compaction, the top CPU consumer is kudu::GetKeyEncoder<kudu::faststring>(kudu::TypeInfo const*). This is called for every _cell_ that is part of the compound key, and is quite expensive since it involves a 'div' instruction.
> A very easy win would be to pre-cache the key encoder objects for each of the columns in the schema. A less-easy but probably bigger win would be to codegen the comparable key encoder for the schema.
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