sql-statements: add sql statements for sql bind #2927
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yikeke
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ran-huang
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Jun 17, 2020
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| This statement binds SQL execution plans at the GLOBAL or SESSION level. The default scope is SESSION. The bound SQL statement is parameterized and stored in the system table. When a SQL query is processed, as long as the parameterized SQL statement and a bound one in the system table are consistent and the system variable `tidb_use_plan_baselines` is set to `on` (the default value is `on`), the corresponding optimizer hint is available. If multiple execution plans are available, the optimizer chooses to bind the plan with the least cost. | ||
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| When a SQL statement has bound execution plans in both GLOBAL and SESSION scopes, because the optimizer ignores the bound execution plan in the GLOBAL scope when it encounters the SESSION binding, the bound execution plan of this statement in the SESSION scope shields the execution plan in the GLOBAL scope. |
Co-authored-by: Ran <huangran@pingcap.com>
Co-authored-by: Ran <huangran@pingcap.com>
Co-authored-by: Ran <huangran@pingcap.com>
Co-authored-by: Ran <huangran@pingcap.com>
Co-authored-by: Ran <huangran@pingcap.com>
Co-authored-by: Ran <huangran@pingcap.com>
Co-authored-by: Ran <huangran@pingcap.com>
Co-authored-by: Ran <huangran@pingcap.com>
Co-authored-by: Ran <huangran@pingcap.com>
ran-huang
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Jun 19, 2020
ran-huang
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Jun 19, 2020
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/merge |
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/run-all-tests |
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@lzmhhh123 merge failed. |
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/merge |
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/run-all-tests |
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Signed-off-by: ti-srebot <ti-srebot@pingcap.com>
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cherry pick to release-4.0 in PR #2967 |
ran-huang
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Jun 19, 2020
Signed-off-by: ti-srebot <ti-srebot@pingcap.com> Co-authored-by: Zhuomin(Charming) Liu <lzmhhh123@gmail.com>
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