diff --git a/system-variables.md b/system-variables.md index 1bb95aa4baabb..4f8e947a4746d 100644 --- a/system-variables.md +++ b/system-variables.md @@ -3159,6 +3159,16 @@ For a system upgraded to v5.0 from an earlier version, if you have not modified - Range: `[1, 100000]` - This variable controls the maximum number of execution plans that can be cached by [Non-prepared plan cache](/sql-non-prepared-plan-cache.md). +### tidb_pre_split_regions New in v8.4.0 + +- Scope: SESSION | GLOBAL +- Persists to cluster: Yes +- Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): No +- Type: Integer +- Default value: `0` +- Range: `[0, 15]` +- This variable is used to set the default number of row split shards for newly created tables. When this variable is set to a non-zero value, TiDB will automatically apply this attribute to tables that allow the use of `PRE_SPLIT_REGIONS` (for example, `NONCLUSTERED` tables) when executing `CREATE TABLE` statements. For more information, see [`PRE_SPLIT_REGIONS`](/sql-statements/sql-statement-split-region.md#pre_split_regions). This variable is typically used in conjunction with [`tidb_shard_row_id_bits`](/system-variables.md#tidb_shard_row_id_bits-new-in-v840) to shard new tables and pre-split the Regions of new tables. + ### tidb_generate_binary_plan New in v6.2.0 > **Note:** @@ -5271,6 +5281,16 @@ SHOW WARNINGS; - Range: `[1, 9223372036854775807]` - This variable controls the maximum number of continuous IDs to be allocated for the [`AUTO_RANDOM`](/auto-random.md) or [`SHARD_ROW_ID_BITS`](/shard-row-id-bits.md) attribute. Generally, `AUTO_RANDOM` IDs or the `SHARD_ROW_ID_BITS` annotated row IDs are incremental and continuous in one transaction. You can use this variable to solve the hotspot issue in large transaction scenarios. +### tidb_shard_row_id_bits New in v8.4.0 + +- Scope: SESSION | GLOBAL +- Persists to cluster: Yes +- Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): No +- Type: Integer +- Default value: `0` +- Range: `[0, 15]` +- This variable is used to set the default number of row ID shards for newly created tables. When this variable is set to a non-zero value, TiDB will automatically apply this attribute to tables that allow the use of `SHARD_ROW_ID_BITS` (for example, `NONCLUSTERED` tables) when executing `CREATE TABLE` statements. For more information, see [`SHARD_ROW_ID_BITS`](/shard-row-id-bits.md). + ### tidb_simplified_metrics > **Note:**