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MySQL如何查看未提交的事务SQL

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发布于 2023-01-16 06:22:20

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文章被收录于专栏：数据库干货铺数据库干货铺

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MySQL中经常遇到事务中的SQL正在执行或执行完成后未提交，如何找出对应的SQL？

1. 查看正在执行的SQL

查看事务中正在执行的SQL方式有多种，例如

1.1 通过processlist查看

会话1：执行1个SQL


mysql> begin;
Query OK, 0 rows affected (0.00 sec)

mysql> select sleep(20),now() ,id from test1;

会话2：开启另一个会话，查看对应的SQL


mysql> select  id ,info  from information_schema.processlist where info is not null;
+----+------------------------------------------------------------------------------+
| id | info                                                                         |
+----+------------------------------------------------------------------------------+
| 36 | select sleep(20),now() ,id from test1                                        |
| 37 | select  id ,info  from information_schema.processlist where info is not null |
+----+------------------------------------------------------------------------------+
2 rows in set (0.00 sec)

可以看到正在执行的SQL，包括自己的SQL的id及内容

1.2 通过events_statements_current查看

会话1：执行1个SQL


mysql> begin;
Query OK, 0 rows affected (0.00 sec)

mysql> select sleep(20),now() ,id from test1;

会话2：查看对应的SQL

mysql> select a.id,a.info, b.thread_id, c.sql_text  from information_schema.processlist  a, performance_schema.threads b, performance_schema.events_statements_current c  where  a.id=b.processlist_id  and b.thread_id = c.thread_id\G
*************************** 1. row ***************************
       id: 36
     info: select sleep(20),now() ,id from test1
thread_id: 76
 sql_text: select sleep(20),now() ,id from test1
*************************** 2. row ***************************
       id: 37
     info: select a.id,a.info, b.thread_id, c.sql_text  from information_schema.processlist  a, performance_schema.threads b, performance_schema.events_statements_current c  where  a.id=b.processlist_id  and b.thread_id = c.thread_id
thread_id: 77
 sql_text: select a.id,a.info, b.thread_id, c.sql_text  from information_schema.processlist  a, performance_schema.threads b, performance_schema.events_statements_current c  where  a.id=b.processlist_id  and b.thread_id = c.thread_id
2 rows in set (0.01 sec)

2. 方式对比

通过processlist和通过events_statements_current区别在于，processlist中能查到的SQL是正在运行的SQL，而运行结束的SQL是看不到的。

会话1：执行1个SQL


mysql> begin;
Query OK, 0 rows affected (0.00 sec)

mysql> select sleep(2),now() ,id from test1;
+----------+---------------------+----+
| sleep(2) | now()               | id |
+----------+---------------------+----+
|        0 | 2023-01-03 22:01:09 |  1 |
+----------+---------------------+----+
1 row in set (2.00 sec)

此时查看事务情况


mysql> select  * from information_schema.innodb_trx\G
*************************** 1. row ***************************
                    trx_id: 421227264232664
                 trx_state: RUNNING
               trx_started: 2023-01-03 22:01:09
     trx_requested_lock_id: NULL
          trx_wait_started: NULL
                trx_weight: 0
       trx_mysql_thread_id: 36
                 trx_query: NULL
       trx_operation_state: NULL
         trx_tables_in_use: 0
         trx_tables_locked: 0
          trx_lock_structs: 0
     trx_lock_memory_bytes: 1128
           trx_rows_locked: 0
         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: 0
          trx_is_read_only: 0
trx_autocommit_non_locking: 0
       trx_schedule_weight: NULL
1 row in set (0.00 sec)

其中trx_mysql_thread_id=36的会话正是我们会话1的线程id,但是我们看不到具体的SQL


mysql> select *  from information_schema.processlist where id=36;
+----+------+-----------+--------+---------+------+-------+------+
| ID | USER | HOST      | DB     | COMMAND | TIME | STATE | INFO |
+----+------+-----------+--------+---------+------+-------+------+
| 36 | root | localhost | testdb | Sleep   |  177 |       | NULL |
+----+------+-----------+--------+---------+------+-------+------+
1 row in set (0.00 sec)

但是此时通过方式2就可以查到


mysql> select a.id,a.info, b.thread_id, c.sql_text  from information_schema.processlist  a, performance_schema.threads b, performance_schema.events_statements_current c  where  a.id=b.processlist_id  and b.thread_id = c.thread_id\G
*************************** 1. row ***************************
       id: 36
     info: NULL
thread_id: 76
 sql_text: select sleep(2),now() ,id from test1
*************************** 2. row ***************************
       id: 37
     info: select a.id,a.info, b.thread_id, c.sql_text  from information_schema.processlist  a, performance_schema.threads b, performance_schema.events_statements_current c  where  a.id=b.processlist_id  and b.thread_id = c.thread_id
thread_id: 77
 sql_text: select a.id,a.info, b.thread_id, c.sql_text  from information_schema.processlist  a, performance_schema.threads b, performance_schema.events_statements_current c  where  a.id=b.processlist_id  and b.thread_id = c.thread_id
2 rows in set (0.00 sec)

注意：此时只能查到一个事务中的多条SQL的最后一个

例如：


mysql> begin;
Query OK, 0 rows affected (0.00 sec)

mysql> select sleep(2),now() ,id from test1;
+----------+---------------------+----+
| sleep(2) | now()               | id |
+----------+---------------------+----+
|        0 | 2023-01-03 22:01:09 |  1 |
+----------+---------------------+----+
1 row in set (2.00 sec)

mysql> select sleep(1),now() ,id from test1;
+----------+---------------------+----+
| sleep(1) | now()               | id |
+----------+---------------------+----+
|        0 | 2023-01-03 22:06:35 |  1 |
+----------+---------------------+----+

会话2查看结果


mysql> select a.id,a.info, b.thread_id, c.sql_text  from information_schema.processlist  a, performance_schema.threads b, performance_schema.events_statements_current c  where  a.id=b.processlist_id  and b.thread_id = c.thread_id\G
*************************** 1. row ***************************
       id: 36
     info: NULL
thread_id: 76
 sql_text: select sleep(1),now() ,id from test1
*************************** 2. row ***************************
       id: 37
     info: select a.id,a.info, b.thread_id, c.sql_text  from information_schema.processlist  a, performance_schema.threads b, performance_schema.events_statements_current c  where  a.id=b.processlist_id  and b.thread_id = c.thread_id
thread_id: 77
 sql_text: select a.id,a.info, b.thread_id, c.sql_text  from information_schema.processlist  a, performance_schema.threads b, performance_schema.events_statements_current c  where  a.id=b.processlist_id  and b.thread_id = c.thread_id
2 rows in set (0.00 sec)