查看MySQL最近的事务执行信息

课题：查看MySQL最近的事务执行信息

*虽然我们可以通过查询慢查询日志查询到一条语句的执行总时长，但是如果数据库中存在一些大事务在执行过程中回滚了，，或者在执行过程中异常终止了，这个时候慢查询日志中是不会记录的，这时需要借助
performance_schema的 eventstransactions-的表来查看与事务相关的记录，在这些表中详细记录了是否有事务被回滚，活跃（长时间未提交的事务也属于活跃事务）活已提交等信息。**

下面模拟几种事务情况，并查看事务事件记录表：

事务事件，默认是没启用的，首先需要进行配置启用

root@localhost [performance_schema]>select * from setup_instruments where name like 'transaction';+-------------+---------+-------+| NAME        | ENABLED | TIMED |+-------------+---------+-------+| transaction | NO      | NO    |+-------------+---------+-------+1 row in set (0.00 sec)root@localhost [performance_schema]>select * from setup_instruments where name like '%transaction%';+--------------------------------------------------------------------------------+---------+-------+| NAME                                                                           | ENABLED | TIMED |+--------------------------------------------------------------------------------+---------+-------+| wait/synch/mutex/sql/LOCK_transaction_cache                                    | NO      | NO    || stage/sql/Waiting for preceding transaction to commit                          | NO      | NO    || stage/sql/Waiting for dependent transaction to commit                          | NO      | NO    || transaction                                                                    | NO      | NO    || memory/performance_schema/events_transactions_summary_by_account_by_event_name | YES     | NO    || memory/performance_schema/events_transactions_summary_by_host_by_event_name    | YES     | NO    || memory/performance_schema/events_transactions_summary_by_thread_by_event_name  | YES     | NO    || memory/performance_schema/events_transactions_history                          | YES     | NO    || memory/performance_schema/events_transactions_summary_by_user_by_event_name    | YES     | NO    || memory/performance_schema/events_transactions_history_long                     | YES     | NO    || memory/sql/THD::transactions::mem_root                                         | YES     | NO    |+--------------------------------------------------------------------------------+---------+-------+11 rows in set (0.00 sec)

查看最近的事务执行信息：

开启事务生产者的参数：

root@localhost [performance_schema]>update setup_instruments set enabled='yes',timed='yes' where name like 'transaction';Query OK, 1 row affected (0.00 sec)Rows matched: 1  Changed: 1  Warnings: 0root@localhost [performance_schema]>update setup_instruments  set enabled='yes' where name like '%transaction%';Query OK, 3 rows affected (0.00 sec)Rows matched: 11  Changed: 3  Warnings: 0

登录mysql会话1，执行清理，避免其他事务的干扰：
提示：线上最好不要直接truncate清除

root@localhost [performance_schema]>truncate events_transactions_current;truncate events_transactions_history; truncate events_transactions_history_long;root@localhost [performance_schema]>select * from events_transactions_current;Empty set (0.00 sec)root@localhost [performance_schema]>select * from events_transactions_history;Empty set (0.00 sec)root@localhost [performance_schema]>select * from events_transactions_history_long;Empty set (0.00 sec)

开启新的会话2，用于执行事务，并模拟事务的回滚：

root@localhost [test001]>begin;Query OK, 0 rows affected (0.00 sec)root@localhost [test001]>update test1_event set username='fox' where id=1;Query OK, 1 row affected (0.00 sec)Rows matched: 1  Changed: 1  Warnings: 0root@localhost [test001]>rollback;Query OK, 0 rows affected (0.00 sec)

在会话1查看当前活跃的事务，查看结果却是空值：

root@localhost [performance_schema]>select THREAD_ID,EVENT_NAME,STATE,TRX_ID,GTID,SOURCE,TIMER_WAIT,ACCESS_MODE,ISOLATION_LEVEL,AUTOCOMMIT,NESTING_EVENT_ID,NESTING_EVENT_TYPE from events_transactions_current\GEmpty set (0.00 sec)root@localhost [(none)]>

root@localhost [performance_schema]>select THREAD_ID,EVENT_NAME,STATE,TRX_ID,GTID,SOURCE,TIMER_WAIT,ACCESS_MODE,ISOLATION_LEVEL,AUTOCOMMIT,NESTING_EVENT_ID,NESTING_EVENT_TYPE from events_transactions_history_long\GEmpty set (0.00 sec)root@localhost [(none)]>

root@localhost [performance_schema]>select THREAD_ID,EVENT_NAME,STATE,TRX_ID,GTID,SOURCE,TIMER_WAIT,ACCESS_MODE,ISOLATION_LEVEL,AUTOCOMMIT,NESTING_EVENT_ID,NESTING_EVENT_TYPE from events_transactions_historyEmpty set (0.00 sec)root@localhost [(none)]>

查看结果却是空值，原因是MySQL消费者参数setup_consumers这一块没开启

root@localhost [performance_schema]>select * from setup_consumers where name like '%transaction%';+----------------------------------+---------+| NAME                             | ENABLED |+----------------------------------+---------+| events_transactions_current      | NO      || events_transactions_history      | NO      || events_transactions_history_long | NO      |+----------------------------------+---------+3 rows in set (0.01 sec)

开启消费者参数：

root@localhost [performance_schema]>update setup_consumers  set enabled='yes' where name like '%transaction%';Query OK, 3 rows affected (0.00 sec)Rows matched: 3  Changed: 3  Warnings: 0root@localhost [performance_schema]>select * from setup_consumers where name like '%transaction%';+----------------------------------+---------+| NAME                             | ENABLED |+----------------------------------+---------+| events_transactions_current      | YES     || events_transactions_history      | YES     || events_transactions_history_long | YES     |+----------------------------------+---------+3 rows in set (0.00 sec)

这些消费参数在分析完事务后记得关闭，关闭命令如下：

update setup_consumers  set enabled='no' where name like '%transaction%';

再次在会话1查看当前活跃的事务：

root@localhost [performance_schema]>select THREAD_ID,EVENT_NAME,STATE,TRX_ID,GTID,SOURCE,TIMER_WAIT,ACCESS_MODE,ISOLATION_LEVEL,AUTOCOMMIT,NESTING_EVENT_ID,NESTING_EVENT_TYPE from events_transactions_current\G*************************** 1. row ***************************         THREAD_ID: 3957325        EVENT_NAME: transaction             STATE: ACTIVE            TRX_ID: NULL              GTID: AUTOMATIC            SOURCE:         TIMER_WAIT: 85087447373000       ACCESS_MODE: READ WRITE   ISOLATION_LEVEL: REPEATABLE READ        AUTOCOMMIT: NO  NESTING_EVENT_ID: 27NESTING_EVENT_TYPE: STATEMENT1 row in set (0.00 sec)

在会话2 上rollback回滚事务：

root@localhost [test001]>begin;Query OK, 0 rows affected (0.00 sec)root@localhost [test001]>update test1_event set username='fox' where id=1;Query OK, 1 row affected (0.00 sec)Rows matched: 1  Changed: 1  Warnings: 0root@localhost [test001]>rollback;Query OK, 0 rows affected (0.00 sec)

再次在会话1查看当前活跃的事务：

root@localhost [performance_schema]>select THREAD_ID,EVENT_NAME,STATE,TRX_ID,GTID,SOURCE,TIMER_WAIT,ACCESS_MODE,ISOLATION_LEVEL,AUTOCOMMIT,NESTING_EVENT_ID,NESTING_EVENT_TYPE from events_transactions_current\G*************************** 1. row ***************************         THREAD_ID: 3957325        EVENT_NAME: transaction             STATE: ROLLED BACK            TRX_ID: NULL              GTID: AUTOMATIC            SOURCE:         TIMER_WAIT: 170837979344000       ACCESS_MODE: READ WRITE   ISOLATION_LEVEL: REPEATABLE READ        AUTOCOMMIT: NO  NESTING_EVENT_ID: 27NESTING_EVENT_TYPE: STATEMENT1 row in set (0.00 sec)

查看事务事件历史记录表：events_transactions_history：

root@localhost [performance_schema]>select THREAD_ID,EVENT_NAME,STATE,TRX_ID,GTID,SOURCE,TIMER_WAIT,ACCESS_MODE,ISOLATION_LEVEL,AUTOCOMMIT,NESTING_EVENT_ID,NESTING_EVENT_TYPE from events_transactions_history\G*************************** 1. row ***************************         THREAD_ID: 3957325        EVENT_NAME: transaction             STATE: ROLLED BACK            TRX_ID: NULL              GTID: AUTOMATIC            SOURCE:         TIMER_WAIT: 170837979344000       ACCESS_MODE: READ WRITE   ISOLATION_LEVEL: REPEATABLE READ        AUTOCOMMIT: NO  NESTING_EVENT_ID: 27NESTING_EVENT_TYPE: STATEMENT2 rows in set (0.00 sec)

root@localhost [test001]>select THREAD_ID,EVENT_NAME,STATE,TRX_ID,GTID,SOURCE,TIMER_WAIT,ACCESS_MODE,ISOLATION_LEVEL,AUTOCOMMIT,NESTING_EVENT_ID,NESTING_EVENT_TYPE from performance_schema.events_transactions_history_long where STATE='ROLLED BACK'\G*************************** 1. row ***************************         THREAD_ID: 3957325        EVENT_NAME: transaction             STATE: ROLLED BACK            TRX_ID: NULL              GTID: AUTOMATIC            SOURCE:         TIMER_WAIT: 170837979344000       ACCESS_MODE: READ WRITE   ISOLATION_LEVEL: REPEATABLE READ        AUTOCOMMIT: NO  NESTING_EVENT_ID: 27NESTING_EVENT_TYPE: STATEMENT1 row in set (0.00 sec)

++++++++++++++++++++++++++++=+++++++++++++++++++++++++
在会话2上模拟正常提交事务：
开始事务

root@localhost [test001]>begin;Query OK, 0 rows affected (0.00 sec)root@localhost [test001]>update test1_event set username='fox' where id=1;Query OK, 1 row affected (0.00 sec)Rows matched: 1  Changed: 1  Warnings: 0

会话1上查看事务信息：

root@localhost [performance_schema]>select THREAD_ID,EVENT_NAME,STATE,TRX_ID,GTID,SOURCE,TIMER_WAIT,ACCESS_MODE,ISOLATION_LEVEL,AUTOCOMMIT,NESTING_EVENT_ID,NESTING_EVENT_TYPE from events_transactions_current\G*************************** 1. row ***************************         THREAD_ID: 3957325        EVENT_NAME: transaction             STATE: ACTIVE            TRX_ID: NULL              GTID: AUTOMATIC            SOURCE:         TIMER_WAIT: 18063808685000       ACCESS_MODE: READ WRITE   ISOLATION_LEVEL: REPEATABLE READ        AUTOCOMMIT: NO  NESTING_EVENT_ID: 75NESTING_EVENT_TYPE: STATEMENT1 row in set (0.00 sec)

在会话2上正常提交事务

root@localhost [test001]>commit;
Query OK, 0 rows affected (0.00 sec)

会话1上查看事务信息：

root@localhost [performance_schema]>root@localhost [performance_schema]>select THREAD_ID,EVENT_NAME,STATE,TRX_ID,GTID,SOURCE,TIMER_WAIT,ACCESS_MODE,ISOLATION_LEVEL,AUTOCOMMIT,NESTING_EVENT_ID,NESTING_EVENT_TYPE from events_transactions_current\G*************************** 1. row ***************************         THREAD_ID: 3957325        EVENT_NAME: transaction             STATE: COMMITTED                                           ##事务已经提交成功            TRX_ID: NULL              GTID: 64a062d1-2e92-11ea-847e-801844ed7bbc:2584551         ##事务正常提交后要记录Gtid的            SOURCE:         TIMER_WAIT: 28245631402000       ACCESS_MODE: READ WRITE   ISOLATION_LEVEL: REPEATABLE READ        AUTOCOMMIT: NO  NESTING_EVENT_ID: 75NESTING_EVENT_TYPE: STATEMENT1 row in set (0.00 sec)

提示：如果一个事务长时间未提交（长时间处于ACTIVE状态）对于这情况，俺们可以查看表nformation_schema.innodb_trx 表直观的看到事务是什么时候开始的，
以及产生这个事务的mysql的线程id号trx_mysql_thread_id: 3957292（也就是会话2的线程id号）

root@localhost [performance_schema]>select * from information_schema.innodb_trx \G*************************** 1. row ***************************                    trx_id: 2594744                 trx_state: RUNNING               trx_started: 2020-02-13 17:53:23     trx_requested_lock_id: NULL          trx_wait_started: NULL                trx_weight: 3       trx_mysql_thread_id: 3957292

performance_schema相关表意思具体可参考下面资料：
配置详解 | performance_schema全方位介绍（二）
http://www.sohu.com/a/253338003_610509
应用示例荟萃 | performance_schema全方位介绍
https://blog.csdn.net/woqutechteam/article/details/81114520