sql/opt: add session setting to disable merged partial stats use in opt#126948
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craig[bot] merged 1 commit intocockroachdb:masterfrom Jul 11, 2024
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Previously, any merged stats created from existing partial stats would always be used by the optimizer. Adds the `optimizer_use_merged_partial_statistics` session setting, which can be used to disable merged stat usage in the optimizer. This is now disabled by default. Merged stats will still be created in the stats cache if partial stats exist, and the creation of partial stats can be controlled using the `enable_create_stats_using_extremes` session setting. Fixes: cockroachdb#95233 See also: cockroachdb#125950 Release note (sql change): Added a session setting, `optimizer_use_merged_partial_statistics`, which can be set to true to enable usage of existing partial statistics merged with full statistics when optimizing a query, which is disabled by default.
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Uzair5162
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complete! 0 of 0 LGTMs obtained (waiting on @DrewKimball)
pkg/sql/vars.go line 843 at r1 (raw file):
return formatBoolAsPostgresSetting(evalCtx.SessionData().OptimizerUseMergedPartialStatistics), nil }, GlobalDefault: globalFalse,
I decided to make this disabled by default to be consistent with enable_create_stats_using_extremes.
DrewKimball
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Reviewed 11 of 11 files at r1, all commit messages.
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Previously, any merged stats created from existing partial stats would always be used by the optimizer. Adds the
optimizer_use_merged_partial_statisticssession setting, which can be used to disable merged stat usage in the optimizer. This is now disabled by default. Merged stats will still be created in the stats cache if partial stats exist, and the creation of partial stats can be controlled using theenable_create_stats_using_extremessession setting.Fixes: #95233
See also: #125950
Release note (sql change): Added a session setting,
optimizer_use_merged_partial_statistics, which can be set to true to enable usage of existing partial statistics merged with full statistics when optimizing a query, which is disabled by default.