zz from http://imysql.com/2015/03/25/mysql-faq-how-to-fetch-latest-trxid.shtml
#先查询 INNODB_TRX 表，看看都有哪些事务
mysql> SELECT * FROM INFORMATION_SCHEMA.INNODB_TRXG *************************** 1. row *************************** trx_id: 17778 -- 当前事务ID trx_state: LOCK WAIT -- 处于锁等待状态，也就是等待其他会话释放锁资源 trx_started: 2015-03-04 10:40:26 trx_requested_lock_id: 17778:82:3:6 -- 欲请求的锁 trx_wait_started: 2015-03-04 10:40:26 trx_weight: 2 -- 大意是该锁影响了2行记录 trx_mysql_thread_id: 657 -- processlist中的线程ID trx_query: update trx_fee set fee=rand()*1000 where id= 4 trx_operation_state: starting index read trx_tables_in_use: 1 trx_tables_locked: 1 trx_lock_structs: 2 trx_lock_memory_bytes: 360 trx_rows_locked: 1 trx_rows_modified: 0 trx_concurrency_tickets: 0 trx_isolation_level: REPEATABLE READ trx_unique_checks: 1 trx_foreign_key_checks: 1 trx_last_foreign_key_error: NULL trx_adaptive_hash_latched: 0 trx_adaptive_hash_timeout: 10000 trx_is_read_only: 0 trx_autocommit_non_locking: 0 *************************** 2. row *************************** trx_id: 17773 trx_state: RUNNING trx_started: 2015-03-04 10:40:23 trx_requested_lock_id: NULL trx_wait_started: NULL trx_weight: 10 trx_mysql_thread_id: 656 trx_query: NULL trx_operation_state: NULL trx_tables_in_use: 0 trx_tables_locked: 0 trx_lock_structs: 2 trx_lock_memory_bytes: 360 trx_rows_locked: 9 trx_rows_modified: 8 trx_concurrency_tickets: 0 trx_isolation_level: REPEATABLE READ trx_unique_checks: 1 trx_foreign_key_checks: 1 trx_last_foreign_key_error: NULL trx_adaptive_hash_latched: 0 trx_adaptive_hash_timeout: 10000 trx_is_read_only: 0 trx_autocommit_non_locking: 0
#再看 INNODB_LOCKS 表，看看都有什么锁
mysql> select * from information_schema.INNODB_LOCKSG *************************** 1. row *************************** lock_id: 17778:82:3:6 --当前锁ID lock_trx_id: 17778 --该锁对应的事务ID lock_mode: X -- 锁类型，排它锁X lock_type: RECORD --锁范围，记录锁：record lock，其他锁范围：间隙锁：gap lock，或者next-key lock（记录锁+间隙锁） lock_table: `test`.`trx_fee` lock_index: PRIMARY --加载在哪个索引上的锁 lock_space: 82 lock_page: 3 lock_rec: 6 lock_data: 4 *************************** 2. row *************************** lock_id: 17773:82:3:6 lock_trx_id: 17773 lock_mode: X lock_type: RECORD lock_table: `test`.`trx_fee` lock_index: PRIMARY lock_space: 82 lock_page: 3 lock_rec: 6 lock_data: 4
#最后看 INNODB_LOCK_WAITS 表，看看当前都有哪些锁等待
mysql> select * from information_schema.INNODB_LOCK_WAITSG *************************** 1. row *************************** requesting_trx_id: 17778 --请求锁的事务ID（等待方） requested_lock_id: 17778:82:3:6 -- 请求锁ID blocking_trx_id: 17773 -- 阻塞该锁的事务ID（当前持有方，待释放） blocking_lock_id: 17773:82:3:6 -- 持有的锁ID
关于INFORMATION_SCHEMA中和InnoDB有关的表用途描述，可以查看手册：21.29 INFORMATION_SCHEMA Tables for InnoDB