MySQL状态变量详解
mysql的状态变量（status variables）记录的mysql服务器的运行状态信息。查看语法如下：
SHOW [GLOBAL | SESSION] STATUS;
SHOW STATUS命令会显示每个服务器变量的名字和值，状态变量是只读的。我们可以在MySQL客户端下运行SHOW STATUS或者在命令行运用mysqladmin extended-status来查看这
些变量。如果使用SQL命令，可以使用LIKE或者WHERE来限制结果。LIKE可以对变量名做标准模式匹配。
SHOW STATUS中混杂了全局和会话变量，其中许多变量有双重域：既是全局变量，也是会话变量，有相同的名字。如果只需要看全局变量，需要改为SHOW GLOBAL STATUS查看
变量详解：
| 变量名 | 值 | 变量说明 |
| Aborted_clients | 1 | 由于客户端未正确关闭连接而终止的连接数 |
| Aborted_connects | 1 | 尝试连接到MySQL服务器失败的次数 |
| Binlog_cache_disk_use | 0 | 使用临时二进制日志缓存但超过binlog_cache_size值并使用临时文件存储来自事务的语句的事务数 |
| Binlog_cache_use | 0 | 使用二进制日志缓存的事务数 |
| Binlog_stmt_cache_disk_use | 0 | 使用二进制日志语句缓存但超过的非事务语句数binlog_stmt_cache_size的值，并使用临时文件存储这些语句 |
| Binlog_stmt_cache_use | 0 | 使用二进制日志语句缓存的非事务性语句数 |
| Bytes_received | 239 | 从所有客户端接收的字节数 |
| Bytes_sent | 176 | 发送到所有客户端的字节数 |
| Com_admin_commands | 0 | admin语句计数 |
| Com_assign_to_keycache | 0 | 缓存索引语句计数 |
| Com_alter_db | 0 | alter database语句计数 |
| Com_alter_db_upgrade | 0 | alter database ... upgrade data directory name 语句计数 |
| Com_alter_event | 0 | alter event语句计数 |
| Com_alter_function | 0 | alter function语句计数 |
| Com_alter_instance | 0 | |
| Com_alter_procedure | 0 | alter procedure语句计数 |
| Com_alter_server | 0 | alter server语句计数 |
| Com_alter_table | 0 | alter table语句计数 |
| Com_alter_tablespace | 0 | alter tablespace语句计数 |
| Com_alter_user | 0 | alter user语句计数 |
| Com_analyze | 0 | analyze语句计数 |
| Com_begin | 0 | begin语句计数 |
| Com_binlog | 0 | binlog语句计数 |
| Com_call_procedure | 0 | call procedure语句计数 |
| Com_change_db | 0 | change database语句计数 |
| Com_change_master | 0 | change master to语句计数 |
| Com_change_repl_filter | 0 | change replication filter语句计数 |
| Com_check | 0 | check语句计数 |
| Com_checksum | 0 | checksum语句计数 |
| Com_commit | 0 | commit语句计数 |
| Com_create_db | 0 | create database语句计数 |
| Com_create_event | 0 | create event语句计数 |
| Com_create_function | 0 | create function语句计数 |
| Com_create_index | 0 | create index语句计数 |
| Com_create_procedure | 0 | create procudure语句计数 |
| Com_create_server | 0 | create server语句计数 |
| Com_create_table | 0 | create table语句计数 |
| Com_create_trigger | 0 | create trigger语句计数 |
| Com_create_udf | 0 | create udf语句计数 |
| Com_create_user | 0 | create user语句计数 |
| Com_create_view | 0 | create view语句计数 |
| Com_dealloc_sql | 0 | deallocate prepare语句计数 |
| Com_delete | 0 | delete语句计数 |
| Com_delete_multi | 0 | multiple table delete语句计数 |
| Com_do | 0 | do语句计数 |
| Com_drop_db | 0 | drop database语句计数 |
| Com_drop_event | 0 | drop event句计数 |
| Com_drop_function | 0 | drop function语句计数 |
| Com_drop_index | 0 | drop index语句计数 |
| Com_drop_procedure | 0 | drop procedure语句计数 |
| Com_drop_server | 0 | drop server语句计数 |
| Com_drop_table | 0 | drop table语句计数 |
| Com_drop_trigger | 0 | drop triger语句计数 |
| Com_drop_user | 0 | drop user语句计数 |
| Com_drop_view | 0 | drop view语句计数 |
| Com_empty_query | 0 | empty语句计数 |
| Com_execute_sql | 0 | execute语句计数 |
| Com_explain_other | 0 | explain for connection语句计数 |
| Com_flush | 0 | flush语句计数 |
| Com_get_diagnostics | 0 | get diagnostics语句计数 |
| Com_grant | 0 | grant语句计数 |
| Com_ha_close | 0 | handler close语句计数 |
| Com_ha_open | 0 | handler open语句计数 |
| Com_ha_read | 0 | handler read语句计数 |
| Com_help | 0 | help语句计数 |
| Com_insert | 0 | insert语句计数 |
| Com_insert_select | 0 | insert..select..语句计数 |
| Com_install_plugin | 0 | install plugin语句计数 |
| Com_kill | 0 | kill语句计数 |
| Com_load | 0 | load语句计数 |
| Com_lock_tables | 0 | lock tables语句计数 |
| Com_optimize | 0 | optimize语句计数 |
| Com_preload_keys | 0 | preload语句计数 |
| Com_prepare_sql | 0 | prepare语句计数 |
| Com_purge | 0 | purge语句计数 |
| Com_purge_before_date | 0 | purge before date语句计数 |
| Com_release_savepoint | 0 | release savepoint语句计数 |
| Com_rename_table | 0 | rename table语句计数 |
| Com_rename_user | 0 | rename user语句计数 |
| Com_repair | 0 | repair语句计数 |
| Com_replace | 0 | replace语句计数 |
| Com_replace_select | 0 | replace select语句计数 |
| Com_reset | 0 | reset语句计数 |
| Com_resignal | 0 | resignal语句计数 |
| Com_revoke | 0 | revoke语句计数 |
| Com_revoke_all | 0 | revoke all语句计数 |
| Com_rollback | 0 | rollback语句计数 |
| Com_rollback_to_savepoint | 0 | rollback to savepoint语句计数 |
| Com_savepoint | 0 | savepoint语句计数 |
| Com_select | 0 | select语句计数 |
| Com_set_option | 0 | set option语句计数 |
| Com_signal | 0 | signal语句计数 |
| Com_show_binlog_events | 0 | show binlog events语句计数 |
| Com_show_binlogs | 0 | show binary logs语句计数 |
| Com_show_charsets | 0 | show charset语句计数 |
| Com_show_collations | 0 | show clooation语句计数 |
| Com_show_create_db | 0 | show create database语句计数 |
| Com_show_create_event | 0 | show create event语句计数 |
| Com_show_create_func | 0 | show create function语句计数 |
| Com_show_create_proc | 0 | show create procedure语句计数 |
| Com_show_create_table | 0 | show create table语句计数 |
| Com_show_create_trigger | 0 | show create trigger语句计数 |
| Com_show_databases | 0 | show databases语句计数 |
| Com_show_engine_logs | 0 | show engine logs语句计数 |
| Com_show_engine_mutex | 0 | show engine mutex语句计数 |
| Com_show_engine_status | 0 | show engine status语句计数 |
| Com_show_events | 0 | show events语句计数 |
| Com_show_errors | 0 | show errors语句计数 |
| Com_show_fields | 0 | show fields语句计数 |
| Com_show_function_code | 0 | show function code语句计数 |
| Com_show_function_status | 0 | show function status语句计数 |
| Com_show_grants | 0 | show grant语句计数 |
| Com_show_keys | 0 | show key语句计数 |
| Com_show_master_status | 0 | show master status语句计数 |
| Com_show_open_tables | 0 | show open tables语句计数 |
| Com_show_plugins | 0 | show plugin语句计数 |
| Com_show_privileges | 0 | show privileges语句计数 |
| Com_show_procedure_code | 0 | show proceudre code语句计数 |
| Com_show_procedure_status | 0 | show procedure status语句计数 |
| Com_show_processlist | 0 | show processlist语句计数 |
| Com_show_profile | 0 | show profile语句计数 |
| Com_show_profiles | 0 | show profiles语句计数 |
| Com_show_relaylog_events | 0 | show relaylog events语句计数 |
| Com_show_slave_hosts | 0 | show slave hosts语句计数 |
| Com_show_slave_status | 0 | show slave status语句计数 |
| Com_show_status | 0 | show status语句计数 |
| Com_show_storage_engines | 0 | show storage engines(show engines)语句计数 |
| Com_show_table_status | 0 | show table status语句计数 |
| Com_show_tables | 0 | show tables语句计数 |
| Com_show_triggers | 0 | show triggers语句计数 |
| Com_show_variables | 0 | show variables语句计数 |
| Com_show_warnings | 0 | show warnings语句计数 |
| Com_show_create_user | 0 | show create user语句计数 |
| Com_shutdown | 0 | shutdown语句计数 |
| Com_slave_start | 0 | start slave语句计数 |
| Com_slave_stop | 0 | stop slave语句计数 |
| Com_group_replication_start | 0 | start group_replication语句计数 |
| Com_group_replication_stop | 0 | stop group_replication语句计数 |
| Com_stmt_execute | 0 | statement execute语句计数 |
| Com_stmt_close | 0 | statement close语句计数 |
| Com_stmt_fetch | 0 | statement fetch语句计数 |
| Com_stmt_prepare | 0 | statement prepare语句计数 |
| Com_stmt_reset | 0 | statement reset语句计数 |
| Com_stmt_send_long_data | 0 | statement execute语句计数 |
| Com_truncate | 0 | statement send long data语句计数 |
| Com_uninstall_plugin | 0 | uninstall plugin语句计数 |
| Com_unlock_tables | 0 | unlock tables语句计数 |
| Com_update | 0 | update语句计数 |
| Com_update_multi | 0 | multiple语句计数 |
| Com_xa_commit | 0 | xa commit语句计数 |
| Com_xa_end | 0 | xa end语句计数 |
| Com_xa_prepare | 0 | xa prepare语句计数 |
| Com_xa_recover | 0 | xa recover语句计数 |
| Com_xa_rollback | 0 | xa rollback语句计数 |
| Com_xa_start | 0 | xa start语句计数 |
| Com_stmt_reprepare | 0 | statement reprepare语句计数 |
| Compression | OFF | |
| Connection_errors_accept | 0 | |
| Connection_errors_internal | 0 | |
| Connection_errors_max_connections | 0 | |
| Connection_errors_peer_address | 0 | |
| Connection_errors_select | 0 | |
| Connection_errors_tcpwrap | 0 | |
| Connections | 34 | |
| Created_tmp_disk_tables | 0 | |
| Created_tmp_files | 5 | |
| Created_tmp_tables | 0 | |
| Delayed_errors | 0 | |
| Delayed_insert_threads | 0 | |
| Delayed_writes | 0 | |
| Flush_commands | 1 | |
| Handler_commit | 0 | |
| Handler_delete | 0 | |
| Handler_discover | 0 | |
| Handler_external_lock | 0 | |
| Handler_mrr_init | 0 | |
| Handler_prepare | 0 | |
| Handler_read_first | 0 | |
| Handler_read_key | 0 | |
| Handler_read_last | 0 | |
| Handler_read_next | 0 | |
| Handler_read_prev | 0 | |
| Handler_read_rnd | 0 | |
| Handler_read_rnd_next | 0 | |
| Handler_rollback | 0 | |
| Handler_savepoint | 0 | |
| Handler_savepoint | 0 | |
| Handler_update | 0 | |
| Handler_write | 0 | |
| Innodb_buffer_pool_dump_status | Dumping of buffer pol not started | |
| Innodb_buffer_pool_load_status | Buffer pool(s) loadcompleted at 181221 13:15:19 | |
| Innodb_buffer_pool_resize_status | ||
| Innodb_buffer_pool_pages_data | 417 | |
| Innodb_buffer_pool_bytes_data | 6832128 | |
| Innodb_buffer_pool_pages_dirty | 0 | |
| Innodb_buffer_pool_bytes_dirty | 0 | |
| Innodb_buffer_pool_pages_flushed | 39 | |
| Innodb_buffer_pool_pages_free | 7775 | |
| Innodb_buffer_pool_pages_misc | 0 | |
| Innodb_buffer_pool_pages_total | 8192 | |
| Innodb_buffer_pool_read_ahead_rnd | 0 | |
| Innodb_buffer_pool_read_ahead | 0 | |
| Innodb_buffer_pool_read_ahead_evicted | 0 | |
| Innodb_buffer_pool_read_requests | 1722 | |
| Innodb_buffer_pool_reads | 383 | |
| Innodb_buffer_pool_wait_free | 0 | |
| Innodb_buffer_pool_write_requests | 345 | |
| Innodb_data_fsyncs | 7 | |
| Innodb_data_pending_fsyncs | 0 | |
| Innodb_data_pending_reads | 0 | |
| Innodb_data_pending_writes | 0 | |
| Innodb_data_read | 7459328 | |
| Innodb_data_reads | 508 | |
| Innodb_data_writes | 56 | |
| Innodb_data_written | 673792 | |
| Innodb_dblwr_pages_written | 2 | |
| Innodb_dblwr_writes | 1 | |
| Innodb_log_waits | 0 | |
| Innodb_log_write_requests | 0 | |
| Innodb_log_writes | 2 | |
| Innodb_os_log_fsyncs | 4 | |
| Innodb_os_log_pending_fsyncs | 0 | |
| Innodb_os_log_pending_writes | 0 | |
| Innodb_os_log_written | 1024 | |
| Innodb_page_size | 16384 | |
| Innodb_pages_created | 35 | |
| Innodb_pages_read | 382 | |
| Innodb_pages_written | 39 | |
| Innodb_row_lock_current_waits | 0 | |
| Innodb_row_lock_time | 0 | |
| Innodb_row_lock_time_avg | 0 | |
| Innodb_row_lock_time_max | 0 | |
| Innodb_row_lock_waits | 0 | |
| Innodb_rows_deleted | 0 | |
| Innodb_rows_inserted | 45 | |
| Innodb_rows_read | 54 | |
| Innodb_rows_updated | 0 | |
| Innodb_num_open_files | 26 | |
| Innodb_truncated_status_writes | 0 | |
| Innodb_available_undo_logs | 128 | |
| Key_blocks_not_flushed | 0 | |
| Key_blocks_unused | 6693 | |
| Key_blocks_used | 5 | |
| Key_read_requests | 8 | |
| Key_reads | 5 | |
| Key_write_requests | 0 | |
| Key_writes | 0 | |
| Last_query_cost | 0.000000 | |
| Last_query_partial_plans | 0 | |
| Locked_connects | 0 | |
| Max_execution_time_exceeded | 0 | |
| Max_execution_time_set | 0 | |
| Max_execution_time_set_failed | 0 | |
| Max_used_connections | 2 | |
| Max_used_connections_time | 2018-12-22 10:27:47 | |
| Not_flushed_delayed_rows | 0 | |
| Ongoing_anonymous_transaction_count | 0 | |
| Open_files | 20 | |
| Open_streams | 0 | |
| Open_table_definitions | 113 | |
| Open_tables | 121 | |
| Opened_files | 162 | |
| Opened_table_definitions | 0 | |
| Opened_tables | 0 | |
| Performance_schema_accounts_lost | 0 | |
| Performance_schema_cond_classes_lost | 0 | |
| Performance_schema_cond_instances_lost | 0 | |
| Performance_schema_digest_lost | 0 | |
| Performance_schema_file_classes_lost | 0 | |
| Performance_schema_file_handles_lost | 0 | |
| Performance_schema_file_instances_lost | 0 | |
| Performance_schema_hosts_lost | 0 | |
| Performance_schema_index_stat_lost | 0 | |
| Performance_schema_locker_lost | 0 | |
| Performance_schema_memory_classes_lost | 0 | |
| Performance_schema_metadata_lock_lost | 0 | |
| Performance_schema_mutex_classes_lost | 0 | |
| Performance_schema_mutex_instances_lost | 0 | |
| Performance_schema_nested_statement_lost | 0 | |
| Performance_schema_prepared_statements_lost | 0 | |
| Performance_schema_program_lost | 0 | |
| Performance_schema_rwlock_classes_lost | 0 | |
| Performance_schema_rwlock_instances_lost | 0 | |
| Performance_schema_session_connect_attrs_lost | 0 | |
| Performance_schema_socket_classes_lost | 0 | |
| Performance_schema_socket_instances_lost | 0 | |
| Performance_schema_stage_classes_lost | 0 | |
| Performance_schema_statement_classes_lost | 0 | |
| Performance_schema_table_handles_lost | 0 | |
| Performance_schema_table_instances_lost | 0 | |
| Performance_schema_table_lock_stat_lost | 0 | |
| Performance_schema_thread_classes_lost | 0 | |
| Performance_schema_thread_instances_lost | 0 | |
| Performance_schema_users_lost | 0 | |
| Prepared_stmt_count | 0 | |
| Qcache_free_blocks | 1 | |
| Qcache_free_memory | 1031832 | |
| Qcache_hits | 0 | |
| Qcache_inserts | 0 | |
| Qcache_lowmem_prunes | 0 | |
| Qcache_not_cached | 26 | |
| Qcache_queries_in_cache | 0 | |
| Qcache_total_blocks | 1 | |
| Queries | 127 | |
| Questions | 2 | |
| Select_full_join | 0 | |
| Select_full_range_join | 0 | |
| Select_range | 0 | |
| Select_range_check | 0 | |
| Select_scan | 0 | |
| Slave_open_temp_tables | 0 | |
| Slow_launch_threads | 0 | |
| Slow_queries | 0 | |
| Sort_merge_passes | 0 | |
| Sort_range | 0 | |
| Sort_rows | 0 | |
| Sort_scan | 0 | |
| Ssl_accept_renegotiates | 0 | |
| Ssl_accepts | 0 | |
| Ssl_callback_cache_hits | 0 | |
| Ssl_cipher | ||
| Ssl_cipher_list | ||
| Ssl_client_connects | 0 | |
| Ssl_connect_renegotiates | 0 | |
| Ssl_ctx_verify_depth | 0 | |
| Ssl_ctx_verify_mode | 0 | |
| Ssl_default_timeout | 0 | |
| Ssl_finished_accepts | 0 | |
| Ssl_finished_connects | 0 | |
| Ssl_server_not_after | ||
| Ssl_server_not_before | ||
| Ssl_session_cache_hits | 0 | |
| Ssl_session_cache_misses | 0 | |
| Ssl_session_cache_mode | ||
| Ssl_session_cache_overflows | 0 | |
| Ssl_session_cache_size | 0 | |
| Ssl_session_cache_timeouts | 0 | |
| Ssl_sessions_reused | 0 | |
| Ssl_used_session_cache_entries | 0 | |
| Ssl_verify_depth | 0 | |
| Ssl_verify_mode | 0 | |
| Ssl_version | ||
| Table_locks_immediate | 143 | |
| Table_locks_waited | 0 | |
| Table_open_cache_hits | 0 | |
| Table_open_cache_misses | 0 | |
| Table_open_cache_overflows | 0 | |
| Tc_log_max_pages_used | 0 | |
| Tc_log_page_size | 0 | |
| Tc_log_page_waits | 0 | |
| Threads_cached | 1 | |
| Threads_connected | 1 | |
| Threads_created | 2 | |
| Threads_running | 1 | |
| Uptime | 114789 | |
| Uptime_since_flush_status | 114789 |