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移除书签SHOW [GLOBAL|SESSION] VARIABLES
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。
语法图
ShowStmt:
ShowTargetFilterable:
GlobalScope:
示例
查看 TiDB 定义的专用系统变量，关于这些变量的含义参见系统变量和语法。
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)
SHOW GLOBAL VARIABLES LIKE 'time_zone%';
+---------------+--------+| Variable_name | Value |+---------------+--------+| time_zone | SYSTEM |+---------------+--------+1 row in set (0.00 sec)
MySQL 兼容性
SHOW [GLOBAL|SESSION] VARIABLES 语句与 MySQL 完全兼容。如发现任何兼容性差异，请在 GitHub 上提交 issue。
