diff --git a/system-variables.md b/system-variables.md index 35af6e2ce30bf..c965574da83b9 100644 --- a/system-variables.md +++ b/system-variables.md @@ -4698,158 +4698,209 @@ SHOW WARNINGS; - Default value: `OFF` - This variable is used to control whether to allow `INSERT`, `REPLACE`, and `UPDATE` statements to operate on the `_tidb_rowid` column. This variable can be used only when you import data using TiDB tools. -### tidb_opt_hash_agg_cost_factor New in v9.0.0 +### tidb_opt_hash_agg_cost_factor New in v8.5.3 and v9.0.0 + +> **Warning:** +> +> This variable is internally used in the [Cost Model](/cost-model.md), and it is **NOT** recommended to modify its value. - Scope: SESSION | GLOBAL - Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): Yes - Type: Float - Range: `[0, 2147483647]` - Default value: `1` -- This variable is internally used in the Cost Model, and it is NOT recommended to modify its value unless directed by TiDB Optimizer Engineering. -### tidb_opt_hash_join_cost_factor New in v9.0.0 +### tidb_opt_hash_join_cost_factor New in v8.5.3 and v9.0.0 + +> **Warning:** +> +> This variable is internally used in the [Cost Model](/cost-model.md), and it is **NOT** recommended to modify its value. - Scope: SESSION | GLOBAL - Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): Yes - Type: Float - Range: `[0, 2147483647]` - Default value: `1` -- This variable is internally used in the Cost Model, and it is NOT recommended to modify its value unless directed by TiDB Optimizer Engineering. -### tidb_opt_index_join_cost_factor New in v9.0.0 +### tidb_opt_index_join_cost_factor New in v8.5.3 and v9.0.0 + +> **Warning:** +> +> This variable is internally used in the [Cost Model](/cost-model.md), and it is **NOT** recommended to modify its value. - Scope: SESSION | GLOBAL - Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): Yes - Type: Float - Range: `[0, 2147483647]` - Default value: `1` -- This variable is internally used in the Cost Model, and it is NOT recommended to modify its value unless directed by TiDB Optimizer Engineering. -### tidb_opt_index_lookup_cost_factor New in v9.0.0 +### tidb_opt_index_lookup_cost_factor New in v8.5.3 and v9.0.0 + +> **Warning:** +> +> This variable is internally used in the [Cost Model](/cost-model.md), and it is **NOT** recommended to modify its value. - Scope: SESSION | GLOBAL - Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): Yes - Type: Float - Range: `[0, 2147483647]` - Default value: `1` -- This variable is internally used in the Cost Model, and it is NOT recommended to modify its value unless directed by TiDB Optimizer Engineering. -### tidb_opt_index_merge_cost_factor New in v9.0.0 +### tidb_opt_index_merge_cost_factor New in v8.5.3 and v9.0.0 + +> **Warning:** +> +> This variable is internally used in the [Cost Model](/cost-model.md), and it is **NOT** recommended to modify its value. - Scope: SESSION | GLOBAL - Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): Yes - Type: Float - Range: `[0, 2147483647]` - Default value: `1` -- This variable is internally used in the Cost Model, and it is NOT recommended to modify its value unless directed by TiDB Optimizer Engineering. -### tidb_opt_index_reader_cost_factor New in v9.0.0 +### tidb_opt_index_reader_cost_factor New in v8.5.3 and v9.0.0 + +> **Warning:** +> +> This variable is internally used in the [Cost Model](/cost-model.md), and it is **NOT** recommended to modify its value. - Scope: SESSION | GLOBAL - Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): Yes - Type: Float - Range: `[0, 2147483647]` - Default value: `1` -- This variable is internally used in the Cost Model, and it is NOT recommended to modify its value unless directed by TiDB Optimizer Engineering. -### tidb_opt_index_scan_cost_factor New in v9.0.0 +### tidb_opt_index_scan_cost_factor New in v8.5.3 and v9.0.0 + +> **Warning:** +> +> This variable is internally used in the [Cost Model](/cost-model.md), and it is **NOT** recommended to modify its value. - Scope: SESSION | GLOBAL - Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): Yes - Type: Float - Range: `[0, 2147483647]` - Default value: `1` -- This variable is internally used in the Cost Model, and it is NOT recommended to modify its value unless directed by TiDB Optimizer Engineering. -### tidb_opt_limit_cost_factor New in v9.0.0 +### tidb_opt_limit_cost_factor New in v8.5.3 and v9.0.0 + +> **Warning:** +> +> This variable is internally used in the [Cost Model](/cost-model.md), and it is **NOT** recommended to modify its value. - Scope: SESSION | GLOBAL - Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): Yes - Type: Float - Range: `[0, 2147483647]` - Default value: `1` -- This variable is internally used in the Cost Model, and it is NOT recommended to modify its value unless directed by TiDB Optimizer Engineering. -### tidb_opt_merge_join_cost_factor New in v9.0.0 +### tidb_opt_merge_join_cost_factor New in v8.5.3 and v9.0.0 + +> **Warning:** +> +> This variable is internally used in the [Cost Model](/cost-model.md), and it is **NOT** recommended to modify its value. - Scope: SESSION | GLOBAL - Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): Yes - Type: Float - Range: `[0, 2147483647]` - Default value: `1` -- This variable is internally used in the Cost Model, and it is NOT recommended to modify its value unless directed by TiDB Optimizer Engineering. -### tidb_opt_sort_cost_factor New in v9.0.0 +### tidb_opt_sort_cost_factor New in v8.5.3 and v9.0.0 + +> **Warning:** +> +> This variable is internally used in the [Cost Model](/cost-model.md), and it is **NOT** recommended to modify its value. - Scope: SESSION | GLOBAL - Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): Yes - Type: Float - Range: `[0, 2147483647]` - Default value: `1` -- This variable is internally used in the Cost Model, and it is NOT recommended to modify its value unless directed by TiDB Optimizer Engineering. -### tidb_opt_stream_agg_cost_factor New in v9.0.0 +### tidb_opt_stream_agg_cost_factor New in v8.5.3 and v9.0.0 + +> **Warning:** +> +> This variable is internally used in the [Cost Model](/cost-model.md), and it is **NOT** recommended to modify its value. - Scope: SESSION | GLOBAL - Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): Yes - Type: Float - Range: `[0, 2147483647]` - Default value: `1` -- This variable is internally used in the Cost Model, and it is NOT recommended to modify its value unless directed by TiDB Optimizer Engineering. -### tidb_opt_table_full_scan_cost_factor New in v9.0.0 +### tidb_opt_table_full_scan_cost_factor New in v8.5.3 and v9.0.0 + +> **Warning:** +> +> This variable is internally used in the [Cost Model](/cost-model.md), and it is **NOT** recommended to modify its value. - Scope: SESSION | GLOBAL - Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): Yes - Type: Float - Range: `[0, 2147483647]` - Default value: `1` -- This variable is internally used in the Cost Model, and it is NOT recommended to modify its value unless directed by TiDB Optimizer Engineering. -### tidb_opt_table_range_scan_cost_factor New in v9.0.0 +### tidb_opt_table_range_scan_cost_factor New in v8.5.3 and v9.0.0 + +> **Warning:** +> +> This variable is internally used in the [Cost Model](/cost-model.md), and it is **NOT** recommended to modify its value. - Scope: SESSION | GLOBAL - Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): Yes - Type: Float - Range: `[0, 2147483647]` - Default value: `1` -- This variable is internally used in the Cost Model, and it is NOT recommended to modify its value unless directed by TiDB Optimizer Engineering. -### tidb_opt_table_reader_cost_factor New in v9.0.0 +### tidb_opt_table_reader_cost_factor New in v8.5.3 and v9.0.0 + +> **Warning:** +> +> This variable is internally used in the [Cost Model](/cost-model.md), and it is **NOT** recommended to modify its value. - Scope: SESSION | GLOBAL - Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): Yes - Type: Float - Range: `[0, 2147483647]` - Default value: `1` -- This variable is internally used in the Cost Model, and it is NOT recommended to modify its value unless directed by TiDB Optimizer Engineering. -### tidb_opt_table_rowid_cost_factor New in v9.0.0 +### tidb_opt_table_rowid_cost_factor New in v8.5.3 and v9.0.0 + +> **Warning:** +> +> This variable is internally used in the [Cost Model](/cost-model.md), and it is **NOT** recommended to modify its value. - Scope: SESSION | GLOBAL - Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): Yes - Type: Float - Range: `[0, 2147483647]` - Default value: `1` -- This variable is internally used in the Cost Model, and it is NOT recommended to modify its value unless directed by TiDB Optimizer Engineering. -### tidb_opt_table_tiflash_scan_cost_factor New in v9.0.0 +### tidb_opt_table_tiflash_scan_cost_factor New in v8.5.3 and v9.0.0 + +> **Warning:** +> +> This variable is internally used in the [Cost Model](/cost-model.md), and it is **NOT** recommended to modify its value. - Scope: SESSION | GLOBAL - Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): Yes - Type: Float - Range: `[0, 2147483647]` - Default value: `1` -- This variable is internally used in the Cost Model, and it is NOT recommended to modify its value unless directed by TiDB Optimizer Engineering. -### tidb_opt_topn_cost_factor New in v9.0.0 +### tidb_opt_topn_cost_factor New in v8.5.3 and v9.0.0 + +> **Warning:** +> +> This variable is internally used in the [Cost Model](/cost-model.md), and it is **NOT** recommended to modify its value. - Scope: SESSION | GLOBAL - Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): Yes - Type: Float - Range: `[0, 2147483647]` - Default value: `1` -- This variable is internally used in the Cost Model, and it is NOT recommended to modify its value unless directed by TiDB Optimizer Engineering. ### tidb_optimizer_selectivity_level