From 36cc1191ebfd5f333e86e66860a321af2d278575 Mon Sep 17 00:00:00 2001 From: Morgan Tocker Date: Fri, 16 Jul 2021 03:59:33 -0600 Subject: [PATCH] system-variables: update for consistency (#5826) --- system-variables.md | 33 ++++++++++++++++++--------------- 1 file changed, 18 insertions(+), 15 deletions(-) diff --git a/system-variables.md b/system-variables.md index ea7a58394fdaa..cf4dbc4929b1f 100644 --- a/system-variables.md +++ b/system-variables.md @@ -114,10 +114,11 @@ mysql> SELECT * FROM t1; - Default value: `utf8mb4` - The character set used for new schemas when no character set is specified in the `CREATE SCHEMA` statement. -### `cte_max_recursion_depth` +### cte_max_recursion_depth -- Scope：SESSION | GLOBAL -- Default value：1000 +- Scope: SESSION | GLOBAL +- Default value: `1000` +- Range: `[0, 4294967295]` - Controls the maximum recursion depth in Common Table Expressions. ### datadir @@ -555,16 +556,6 @@ Constraint checking is always performed in place for pessimistic transactions (d - Default value: `OFF` - This variable is used to set whether to enable the `LIST (COLUMNS) TABLE PARTITION` feature. -### `tidb_partition_prune_mode` New in v5.1 - -> **Warning:** -> -> Currently, the dynamic mode for partitioned tables is an experimental feature. It is not recommended that you use it in the production environment. - -- Scope: SESSION | GLOBAL -- Default value: `static` -- Specifies whether to enable `dynamic` mode for partitioned tables. For details about the dynamic mode, see [Dynamic Mode for Partitioned Tables](/partitioned-table.md#dynamic-mode). - ### tidb_enable_noop_functions New in v4.0 - Scope: SESSION | GLOBAL @@ -660,7 +651,7 @@ Query OK, 0 rows affected (0.09 sec) - Default value: `ON` - This variable is used to control whether to enable the support for window functions. Note that window functions may use reserved keywords. This might cause SQL statements that could be executed normally cannot be parsed after upgrading TiDB. In this case, you can set `tidb_enable_window_function` to `OFF`. -### `tidb_enforce_mpp` New in v5.1 +### tidb_enforce_mpp New in v5.1 - Scope: SESSION - Default value: `OFF`. To change this default value, modify the [`performance.enforce-mpp`](/tidb-configuration-file.md#enforce-mpp) configuration value. @@ -760,6 +751,7 @@ For a system upgraded to v5.0 from an earlier version, if you have not modified - Scope: GLOBAL - Default value: `10m0s` +- Range: `[10m0s, 8760h0m0s]` - The time limit during which data is retained for each GC, in the format of Go Duration. When a GC happens, the current time minus this value is the safe point. > **Note:** @@ -773,6 +765,7 @@ For a system upgraded to v5.0 from an earlier version, if you have not modified - Scope: GLOBAL - Default value: `10m0s` +- Range: `[10m0s, 8760h0m0s]` - Specifies the GC interval, in the format of Go Duration, for example, `"1h30m"`, and `"15m"` ### tidb_gc_scan_lock_mode New in v5.0 @@ -1108,6 +1101,16 @@ explain select * from t where age=5; - 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_partition_prune_mode New in v5.1 + +> **Warning:** + +> Currently, the dynamic pruning mode for partitioned tables is an experimental feature. It is not recommended that you use it in the production environment. + +- Scope: SESSION | GLOBAL +- Default value: `static` +- Specifies whether to enable `dynamic` mode for partitioned tables. For details about the dynamic pruning mode, see [Dynamic Pruning Mode for Partitioned Tables](/partitioned-table.md#dynamic-mode). + ### tidb_pprof_sql_cpu New in v4.0 - Scope: INSTANCE @@ -1368,7 +1371,7 @@ This variable is an alias for _transaction_isolation_. ### warning_count - Scope: SESSION -- Default value: 0 +- Default value: `0` - This read-only variable indicates the number of warnings that occurred in the statement that was previously executed. ### windowing_use_high_precision