今天一个朋友想查看一下的MySQL层事务提交状态经历的过程，比如我们常说的prapare flush sync commit 几个阶段，但是找了一下发现视乎没有视图可以看到一共看了3个地方： - information_schema.INNODB_TRX 的trx_state字段 - information_schema.INNODB_TRX 的trx_operation_state字段 - performance_schema.events_transactions_current 的STATE字段 其中information_schema.INNODB_TRX表由函数fill_innodb_trx_from_cache进行填充，最终发现他们均不能满足需求。 欢迎关注我的《深入理解MySQL主从原理 32讲 》，如下：  如果图片不能显示可查看下面链接： https://www.jianshu.com/p/d636215d767f ###一、information_schema.INNODB_TRX 的trx_state字段 这个字段源码注释如下： ``` trx_que_t que_state; /*!< valid when trx->state == TRX_STATE_ACTIVE: TRX_QUE_RUNNING, TRX_QUE_LOCK_WAIT, ... */ /** Transaction execution states when trx->state == TRX_STATE_ACTIVE */ enum trx_que_t { TRX_QUE_RUNNING, /*!< transaction is running */ TRX_QUE_LOCK_WAIT, /*!< transaction is waiting for a lock */ TRX_QUE_ROLLING_BACK, /*!< transaction is rolling back */ TRX_QUE_COMMITTING /*!< transaction is committing */ }; ``` 在测试中发现即便是commit下的也会是RUNNING状态，如下：  因此主要取值有3个 - TRX_QUE_RUNNING RUNNING - TRX_QUE_LOCK_WAIT LOCK WAIT - TRX_QUE_ROLLING_BACK ROLLING BACK 但是COMMITTING状态正确commit流程不触发。 ###二、information_schema.INNODB_TRX 的trx_operation_state字段 这个字段取值很多，标记了事务的各个阶段，主要来自于trx_t::op_info，在commit阶段有如下取值：  其中preparing 和committing分别由函数trx_prepare_for_mysql和trx_commit_for_mysql进入，做完innodb层的prepare和commit后就会更改为NULL，实际的binlog的flush sync阶段不包含其中，实际也很好测试，可以做一个大事务，会发现 commit期间基本处于NULL状态： ``` mysql> select * from information_schema.INNODB_TRX \G *************************** 1. row *************************** trx_id: 66206 trx_state: RUNNING trx_started: 2019-08-23 23:44:05 trx_requested_lock_id: NULL trx_wait_started: NULL trx_weight: 1046257 trx_mysql_thread_id: 4 trx_query: commit trx_operation_state: NULL trx_tables_in_use: 0 trx_tables_locked: 1 trx_lock_structs: 2025 trx_lock_memory_bytes: 319960 trx_rows_locked: 1044232 trx_rows_modified: 1044232 trx_concurrency_tickets: 0 trx_isolation_level: READ COMMITTED ... ``` ###三、performance_schema.events_transactions_current 的STATE字段 这个值也只有3个取值： ``` enum enum_transaction_state { TRANS_STATE_ACTIVE= 1, TRANS_STATE_COMMITTED= 2, TRANS_STATE_ROLLED_BACK= 3 }; ``` TRANS_STATE_ACTIVE到TRANS_STATE_COMMITTED的转换会出现在innodb层提交完成后，也就是这个时候实际上整个prapare flush sync commit 已经结束了，之前一直除以ACTIVE状态，用处不大。如下： ``` #0 pfs_end_transaction_v1 (locker=0x7ffee0014ba8, commit=1 '\001') at /mysqldata/percona-server-locks-detail-5.7.22/storage/perfschema/pfs.cc:6116 #1 0x0000000000f7d177 in inline_mysql_commit_transaction (locker=0x7ffee0014ba8) at /mysqldata/percona-server-locks-detail-5.7.22/include/mysql/psi/mysql_transaction.h:206 #2 0x0000000000f8026c in ha_commit_trans (thd=0x7ffee00129d0, all=true, ignore_global_read_lock=false) at /mysqldata/percona-server-locks-detail-5.7.22/sql/handler.cc:1843 #3 0x00000000016dcd2f in trans_commit (thd=0x7ffee00129d0) at /mysqldata/percona-server-locks-detail-5.7.22/sql/transaction.cc:239 #4 0x00000000015cf466 in mysql_execute_command (thd=0x7ffee00129d0, first_level=true) at /mysqldata/percona-server-locks-detail-5.7.22/sql/sql_parse.cc:4526 #5 0x00000000015d2fde in mysql_parse (thd=0x7ffee00129d0, parser_state=0x7fffec5ee600) at /mysqldata/percona-server-locks-detail-5.7.22/sql/sql_parse.cc:5901 #6 0x00000000015c6b72 in dispatch_command (thd=0x7ffee00129d0, com_data=0x7fffec5eed70, command=COM_QUERY) at /mysqldata/percona-server-locks-detail-5.7.22/sql/sql_parse.cc:1490 #7 0x00000000015c58ff in do_command (thd=0x7ffee00129d0) at /mysqldata/percona-server-locks-detail-5.7.22/sql/sql_parse.cc:1021 #8 0x000000000170e578 in handle_connection (arg=0x67d6410) at /mysqldata/percona-server-locks-detail-5.7.22/sql/conn_handler/connection_handler_per_thread.cc:312 #9 0x0000000001945538 in pfs_spawn_thread (arg=0x67be520) at /mysqldata/percona-server-locks-detail-5.7.22/storage/perfschema/pfs.cc:2190 #10 0x00007ffff7bcfaa1 in start_thread () from /lib64/libpthread.so.0 #11 0x00007ffff6b37c4d in clone () from /lib64/libc.so.6 (gdb) n 6117 DBUG_ASSERT(state != NULL); (gdb) n 6119 ulonglong timer_end= 0; (gdb) n 6120 ulonglong wait_time= 0; (gdb) n 6121 uint flags= state->m_flags; (gdb) n 6123 if (flags & STATE_FLAG_TIMED) (gdb) n 6125 timer_end= state->m_timer(); (gdb) n 6126 wait_time= timer_end - state->m_timer_start; (gdb) n 6131 if (flags & STATE_FLAG_THREAD) (gdb) n 6133 PFS_thread *pfs_thread= reinterpret_cast<PFS_thread *> (state->m_thread); (gdb) n 6134 DBUG_ASSERT(pfs_thread != NULL); (gdb) n 6137 stat= &pfs_thread->write_instr_class_transactions_stats()[GLOBAL_TRANSACTION_INDEX]; (gdb) n 6139 if (flags & STATE_FLAG_EVENT) (gdb) n 6141 PFS_events_transactions *pfs= reinterpret_cast<PFS_events_transactions*> (state->m_transaction); (gdb) n 6142 DBUG_ASSERT(pfs != NULL); (gdb) n 6145 if (unlikely(pfs->m_class == NULL)) (gdb) n 6148 pfs->m_timer_end= timer_end; (gdb) n 6149 pfs->m_end_event_id= pfs_thread->m_event_id; (gdb) n 6151 pfs->m_state= (commit ? TRANS_STATE_COMMITTED : TRANS_STATE_ROLLED_BACK); (gdb) p pfs->m_state $1 = TRANS_STATE_ACTIVE ``` 因此上面3个取值都不是那么有用。