| title | summary | category |
|---|---|---|
SHOW [GLOBAL|SESSION] VARIABLES |
TiDB 数据库中 SHOW [GLOBAL|SESSION] VARIABLES 的使用概况。 |
reference |
SHOW [GLOBAL|SESSION] VARIABLES 语句用于显示 GLOBAL 或 SESSION 范围的变量列表。如果未指定范围，则应用默认范围 SESSION。
ShowStmt:
ShowTargetFilterable:
GlobalScope:
{{< copyable "sql" >}}
SHOW GLOBAL VARIABLES LIKE 'tidb%';+-------------------------------------+---------------+
| Variable_name | Value |
+-------------------------------------+---------------+
| tidb_ddl_error_count_limit | 512 |
| tidb_dml_batch_size | 20000 |
| tidb_force_priority | NO_PRIORITY |
| tidb_batch_insert | 0 |
| tidb_skip_utf8_check | 0 |
| tidb_backoff_lock_fast | 100 |
| tidb_opt_join_reorder_threshold | 0 |
| tidb_auto_analyze_end_time | 23:59 +0000 |
| tidb_slow_log_threshold | 300 |
| tidb_opt_correlation_exp_factor | 1 |
| tidb_mem_quota_sort | 34359738368 |
| tidb_current_ts | 0 |
| tidb_ddl_reorg_batch_size | 256 |
| tidb_checksum_table_concurrency | 4 |
| tidb_check_mb4_value_in_utf8 | 1 |
| tidb_distsql_scan_concurrency | 15 |
| tidb_optimizer_selectivity_level | 0 |
| tidb_opt_agg_push_down | 0 |
| tidb_max_chunk_size | 1024 |
| tidb_low_resolution_tso | 0 |
| tidb_index_lookup_size | 20000 |
| tidb_skip_isolation_level_check | 0 |
| tidb_opt_write_row_id | 0 |
| tidb_wait_split_region_finish | 1 |
| tidb_index_lookup_join_concurrency | 4 |
| tidb_mem_quota_indexlookupjoin | 34359738368 |
| tidb_replica_read | leader |
| tidb_ddl_reorg_priority | PRIORITY_LOW |
| tidb_batch_commit | 0 |
| tidb_mem_quota_mergejoin | 34359738368 |
| tidb_mem_quota_query | 34359738368 |
| tidb_batch_delete | 0 |
| tidb_build_stats_concurrency | 4 |
| tidb_enable_index_merge | 0 |
| tidb_enable_radix_join | 0 |
| tidb_retry_limit | 10 |
| tidb_query_log_max_len | 2048 |
| tidb_config | |
| tidb_ddl_reorg_worker_cnt | 4 |
| tidb_opt_insubq_to_join_and_agg | 1 |
| tidb_enable_vectorized_expression | 1 |
| tidb_mem_quota_hashjoin | 34359738368 |
| tidb_disable_txn_auto_retry | 1 |
| tidb_enable_window_function | 1 |
| tidb_init_chunk_size | 32 |
| tidb_constraint_check_in_place | 0 |
| tidb_wait_split_region_timeout | 300 |
| tidb_hash_join_concurrency | 5 |
| tidb_enable_fast_analyze | 0 |
| tidb_enable_cascades_planner | 0 |
| tidb_txn_mode | |
| tidb_index_serial_scan_concurrency | 1 |
| tidb_projection_concurrency | 4 |
| tidb_enable_noop_functions | 0 |
| tidb_index_lookup_concurrency | 4 |
| tidb_hashagg_partial_concurrency | 4 |
| tidb_general_log | 0 |
| tidb_enable_streaming | 0 |
| tidb_backoff_weight | 2 |
| tidb_mem_quota_topn | 34359738368 |
| tidb_scatter_region | 0 |
| tidb_index_join_batch_size | 25000 |
| tidb_snapshot | |
| tidb_expensive_query_time_threshold | 60 |
| tidb_slow_query_file | tidb-slow.log |
| tidb_auto_analyze_ratio | 0.5 |
| tidb_enable_table_partition | auto |
| tidb_auto_analyze_start_time | 00:00 +0000 |
| tidb_mem_quota_nestedloopapply | 34359738368 |
| tidb_mem_quota_indexlookupreader | 34359738368 |
| tidb_hashagg_final_concurrency | 4 |
| tidb_opt_correlation_threshold | 0.9 |
+-------------------------------------+---------------+
68 rows in set (0.01 sec)
{{< copyable "sql" >}}
SHOW GLOBAL VARIABLES LIKE 'time_zone%';+---------------+--------+
| Variable_name | Value |
+---------------+--------+
| time_zone | SYSTEM |
+---------------+--------+
1 row in set (0.00 sec)
SHOW [GLOBAL|SESSION] VARIABLES 语句与 MySQL 完全兼容。如有任何兼容性差异，请在 GitHub 上提交 issue。