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SHOW [GLOBAL|SESSION] VARIABLES

This statement shows a list of variables for the scope of either GLOBAL or SESSION. If no scope is specified, the default scope of SESSION will apply.

Synopsis

ShowVariablesStmt
SHOW GLOBAL SESSION VARIABLES ShowLikeOrWhere
ShowLikeOrWhere
LIKE SimpleExpr WHERE Expression

Examples

以下示例演示了如何使用 SHOW [GLOBAL|SESSION] VARIABLES 语句显示名称或值匹配特定模式的变量。有关这些变量的详细说明，请参见 System Variables。

mysql> SHOW GLOBAL VARIABLES LIKE 'tidb_stmt_summary%';
+-------------------------------------+---------------------+
| Variable_name                       | Value               |
+-------------------------------------+---------------------+
| tidb_stmt_summary_enable_persistent | OFF                 |
| tidb_stmt_summary_file_max_backups  | 0                   |
| tidb_stmt_summary_file_max_days     | 3                   |
| tidb_stmt_summary_file_max_size     | 64                  |
| tidb_stmt_summary_filename          | tidb-statements.log |
| tidb_stmt_summary_history_size      | 24                  |
| tidb_stmt_summary_internal_query    | OFF                 |
| tidb_stmt_summary_max_sql_length    | 4096                |
| tidb_stmt_summary_max_stmt_count    | 3000                |
| tidb_stmt_summary_refresh_interval  | 1800                |
+-------------------------------------+---------------------+
10 rows in set (0.001 sec)

mysql> SHOW GLOBAL VARIABLES LIKE 'time_zone%';
+---------------+--------+
| Variable_name | Value  |
+---------------+--------+
| time_zone     | SYSTEM |
+---------------+--------+
1 row in set (0.00 sec)

mysql> SHOW VARIABLES WHERE Variable_name="tidb_window_concurrency";
+-------------------------+-------+
| Variable_name           | Value |
+-------------------------+-------+
| tidb_window_concurrency | -1    |
+-------------------------+-------+
1 row in set (0.00 sec)

mysql> SHOW VARIABLES WHERE Value=300;
+--------------------------------+-------+
| Variable_name                  | Value |
+--------------------------------+-------+
| ddl_slow_threshold             | 300   |
| delayed_insert_timeout         | 300   |
| innodb_purge_batch_size        | 300   |
| key_cache_age_threshold        | 300   |
| slave_checkpoint_period        | 300   |
| tidb_slow_log_threshold        | 300   |
| tidb_wait_split_region_timeout | 300   |
+--------------------------------+-------+
7 rows in set (0.00 sec)

MySQL compatibility

The SHOW [GLOBAL|SESSION] VARIABLES statement in TiDB is fully compatible with MySQL. If you find any compatibility differences, report a bug.

See also