Important

You are viewing the documentation of TiDB v6.0 (DMR). PingCAP does not provide bug fixes for v6.0. Any bugs will be fixed in future releases.

For general purposes, please use the latest LTS version of the TiDB database.

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

ShowStmt:

ShowStmt

ShowTargetFilterable:

ShowTargetFilterable

GlobalScope:

GlobalScope

Examples

List all TiDB specific variables. For detailed description, refer to System Variables.

mysql> SHOW GLOBAL VARIABLES LIKE 'tidb%';
+-------------------------------------+---------------------+
| Variable_name                       | Value               |
+-------------------------------------+---------------------+
| tidb_allow_batch_cop                | 0                   |
| tidb_allow_remove_auto_inc          | 0                   |
| tidb_auto_analyze_end_time          | 23:59 +0000         |
| tidb_auto_analyze_ratio             | 0.5                 |
| tidb_auto_analyze_start_time        | 00:00 +0000         |
| tidb_backoff_lock_fast              | 100                 |
| tidb_backoff_weight                 | 2                   |
| tidb_batch_commit                   | 0                   |
| tidb_batch_delete                   | 0                   |
| tidb_batch_insert                   | 0                   |
| tidb_build_stats_concurrency        | 4                   |
| tidb_capture_plan_baselines         | off                 |
| tidb_check_mb4_value_in_utf8        | 1                   |
| tidb_checksum_table_concurrency     | 4                   |
| tidb_config                         |                     |
| tidb_constraint_check_in_place      | 0                   |
| tidb_current_ts                     | 0                   |
| tidb_ddl_error_count_limit          | 512                 |
| tidb_ddl_reorg_batch_size           | 256                 |
| tidb_ddl_reorg_priority             | PRIORITY_LOW        |
| tidb_ddl_reorg_worker_cnt           | 4                   |
| tidb_disable_txn_auto_retry         | 1                   |
| tidb_distsql_scan_concurrency       | 15                  |
| tidb_dml_batch_size                 | 20000               |
| tidb_enable_cascades_planner        | 0                   |
| tidb_enable_chunk_rpc               | 1                   |
| tidb_enable_collect_execution_info  | 1                   |
| tidb_enable_fast_analyze            | 0                   |
| tidb_enable_index_merge             | 0                   |
| tidb_enable_noop_functions          | 0                   |
| tidb_enable_radix_join              | 0                   |
| tidb_enable_slow_log                | 1                   |
| tidb_enable_stmt_summary            | 1                   |
| tidb_enable_table_partition         | on                  |
| tidb_enable_vectorized_expression   | 1                   |
| tidb_enable_window_function         | 1                   |
| tidb_evolve_plan_baselines          | off                 |
| tidb_evolve_plan_task_end_time      | 23:59 +0000         |
| tidb_evolve_plan_task_max_time      | 600                 |
| tidb_evolve_plan_task_start_time    | 00:00 +0000         |
| tidb_expensive_query_time_threshold | 60                  |
| tidb_force_priority                 | NO_PRIORITY         |
| tidb_general_log                    | 0                   |
| tidb_hash_join_concurrency          | 5                   |
| tidb_hashagg_final_concurrency      | 4                   |
| tidb_hashagg_partial_concurrency    | 4                   |
| tidb_index_join_batch_size          | 25000               |
| tidb_index_lookup_concurrency       | 4                   |
| tidb_index_lookup_join_concurrency  | 4                   |
| tidb_index_lookup_size              | 20000               |
| tidb_index_serial_scan_concurrency  | 1                   |
| tidb_init_chunk_size                | 32                  |
| tidb_isolation_read_engines         | tikv, tiflash, tidb |
| tidb_low_resolution_tso             | 0                   |
| tidb_max_chunk_size                 | 1024                |
| tidb_max_delta_schema_count         | 1024                |
| tidb_mem_quota_hashjoin             | 34359738368         |
| tidb_mem_quota_indexlookupjoin      | 34359738368         |
| tidb_mem_quota_indexlookupreader    | 34359738368         |
| tidb_mem_quota_mergejoin            | 34359738368         |
| tidb_mem_quota_nestedloopapply      | 34359738368         |
| tidb_mem_quota_query                | 1073741824          |
| tidb_mem_quota_sort                 | 34359738368         |
| tidb_mem_quota_topn                 | 34359738368         |
| tidb_metric_query_range_duration    | 60                  |
| tidb_metric_query_step              | 60                  |
| tidb_opt_agg_push_down              | 0                   |
| tidb_opt_concurrency_factor         | 3                   |
| tidb_opt_copcpu_factor              | 3                   |
| tidb_opt_correlation_exp_factor     | 1                   |
| tidb_opt_correlation_threshold      | 0.9                 |
| tidb_opt_cpu_factor                 | 3                   |
| tidb_opt_desc_factor                | 3                   |
| tidb_opt_disk_factor                | 1.5                 |
| tidb_opt_distinct_agg_push_down     | 0                   |
| tidb_opt_insubq_to_join_and_agg     | 1                   |
| tidb_opt_join_reorder_threshold     | 0                   |
| tidb_opt_memory_factor              | 0.001               |
| tidb_opt_network_factor             | 1                   |
| tidb_opt_scan_factor                | 1.5                 |
| tidb_opt_seek_factor                | 20                  |
| tidb_opt_write_row_id               | 0                   |
| tidb_optimizer_selectivity_level    | 0                   |
| tidb_pprof_sql_cpu                  | 0                   |
| tidb_projection_concurrency         | 4                   |
| tidb_query_log_max_len              | 4096                |
| tidb_record_plan_in_slow_log        | 1                   |
| tidb_replica_read                   | leader              |
| tidb_retry_limit                    | 10                  |
| tidb_row_format_version             | 2                   |
| tidb_scatter_region                 | 0                   |
| tidb_skip_isolation_level_check     | 0                   |
| tidb_skip_utf8_check                | 0                   |
| tidb_slow_log_threshold             | 300                 |
| tidb_slow_query_file                | tidb-slow.log       |
| tidb_snapshot                       |                     |
| tidb_stmt_summary_history_size      | 24                  |
| tidb_stmt_summary_internal_query    | 0                   |
| tidb_stmt_summary_max_sql_length    | 4096                |
| tidb_stmt_summary_max_stmt_count    | 3000                |
| tidb_stmt_summary_refresh_interval  | 1800                |
| tidb_store_limit                    | 0                   |
| tidb_txn_mode                       |                     |
| tidb_use_plan_baselines             | on                  |
| tidb_wait_split_region_finish       | 1                   |
| tidb_wait_split_region_timeout      | 300                 |
| tidb_window_concurrency             | 4                   |
+-------------------------------------+---------------------+
108 rows in set (0.01 sec)

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

MySQL compatibility

This statement is understood to be fully compatible with MySQL. Any compatibility differences should be reported via an issue on GitHub.

See also

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