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Posted to issues-all@impala.apache.org by "ASF subversion and git services (Jira)" <ji...@apache.org> on 2023/10/24 05:01:00 UTC
[jira] [Commented] (IMPALA-5081) Expose IR optimization level via query option
[ https://issues.apache.org/jira/browse/IMPALA-5081?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17778929#comment-17778929 ]
ASF subversion and git services commented on IMPALA-5081:
---------------------------------------------------------
Commit 7230c57f6784cdb99080f3d4c8b679c33b54da21 in impala's branch refs/heads/master from Michael Smith
[ https://gitbox.apache.org/repos/asf?p=impala.git;h=7230c57f6 ]
IMPALA-5081: Add codegen_opt_level query option
Adds the 'codegen_opt_level' query option to select LLVM optimization
level for generated code. Retains the prior behavior - O2 - as default.
If optimization level is changed for an entry already in cache, the
cache entry will be used unless the new optimization level is higher
than the cached level.
Adds additional counters for NumOptimizedFunctions and
NumOptimizedInstructions, which allow observing some impacts from
codegen optimization. These additional counters, and tracking opt level
for cached entries, increases the size of each cached entry.
Adds unit tests for all optimizition levels checking
- that small functions are inlined at higher levels (as a way to verify
that optimization level has an effect)
- codegen cache entries are updated when optimizing the same fragment at
a higher level, and not updated the rest of the time
Change-Id: I371f8758b6552263e91a1fbfd9a6e1c28e1fa2bd
Reviewed-on: http://gerrit.cloudera.org:8080/20399
Reviewed-by: Impala Public Jenkins <im...@cloudera.com>
Tested-by: Impala Public Jenkins <im...@cloudera.com>
> Expose IR optimization level via query option
> ---------------------------------------------
>
> Key: IMPALA-5081
> URL: https://issues.apache.org/jira/browse/IMPALA-5081
> Project: IMPALA
> Issue Type: Improvement
> Components: Backend
> Reporter: Michael Ho
> Assignee: Michael Smith
> Priority: Minor
> Labels: codegen
> Fix For: Impala 4.4.0
>
>
> Certain queries may spend a lot of time in the IR optimization. Currently, there is a start-up option to disable optimization in LLVM. However, it may be of inconvenience to users to have to restart the entire Impala cluster to just use that option. This JIRA aims at exploring exposing a query option for users to choose the optimization level for a given query (e.g. we can have a level which just only have a dead code elimination pass or no optimization at all).
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