diff --git a/system-variables.md b/system-variables.md index 6ad5c710e3ace..ace88616231e0 100644 --- a/system-variables.md +++ b/system-variables.md @@ -4297,6 +4297,24 @@ mysql> desc select count(distinct a) from test.t; - Default value: `OFF` - This variable controls whether to enable the [Cross-database binding](/sql-plan-management.md#cross-database-binding) feature. +### tidb_opt_enable_no_decorrelate_in_select New in v8.5.4 + +- Scope: SESSION | GLOBAL +- Persists to cluster: Yes +- Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): Yes +- Type: Boolean +- Default value: `OFF` +- This variable controls whether the optimizer applies the [`NO_DECORRELATE()`](/optimizer-hints.md#no_decorrelate) hint for all queries that contain a subquery in the `SELECT` list. + +### tidb_opt_enable_semi_join_rewrite New in v8.5.4 + +- Scope: SESSION | GLOBAL +- Persists to cluster: Yes +- Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): No +- Type: Boolean +- Default value: `OFF` +- This variable controls whether the optimizer applies the [`SEMI_JOIN_REWRITE()`](/optimizer-hints.md#semi_join_rewrite) hint for all queries that contain subqueries. + ### tidb_opt_fix_control New in v6.5.3 and v7.1.0