Contrib Fake PR : Bug#116716 - Allow Setting Nb Thread for Tablespace Duplicate Check (startup). #15
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This PR allows setting the number of threads for InnoDB Tablespace Duplicate Check, implementing the feature request Bug #116716 : Allow Setting Nb Thread for Tablespace Duplicate Check (startup).
This is a "Contrib Fake PR". It is there so people can comment on this work in case it needs adjustments. This has been contributed on 2024-12-03 as a patch file in Bug #116716. More about Fake PR in the RFC blog post, section Fake PRs and my Way of Working on MySQL Contributions.
This PR merges on 9.1.0, and the patch file also applies on 8.4.3 and 8.0.40.
For allowing setting the number of threads for InnoDB Tablespace Duplicate Check, this PR introduces a new global variable : innodb_tablespace_duplicate_check_threads. The default value is -1, which means the already implemented heuristic is used for setting the number of threads. A value of 0 to MAX VAL overrides the number of threads of the heuristic.
Ideally, in addition to being included in a next Innovation Release, this would be back ported in 8.4 and 8.0. The default value of the global variable introduced by this change is backward compatible with 8.4 and 8.0, so I think this change does not introduce any compatibility problems. And as this change introduces a potential performance improvement making startup faster, I think there is value in back-porting it.
Examples on how this PR is useful was added in Bug #116716.
I also blogged about this: InnoDB Tablespace Duplicate Check Threads.