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
SHOWGLOBALSESSIONVARIABLESShowLikeOrWhere
ShowLikeOrWhere
LIKESimpleExprWHEREExpression

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_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_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> 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