如何查看MySQL connection id连接id

每个MySQL连接，都有一个连接ID，可以通过 connection_id()查看。

连接id也可以通过以下方式查看：

• show processlist中id列
• information_schema.processlist的id列
• performance_schema.threads的processlist_id 列

下面通过具体命令查看连接id。

查看连接id:

mysql> select connection_id();
+-----------------+
| connection_id() |
+-----------------+
|              15           |
+-----------------+
1 row in set (0.00 sec)

查看show processlist:

mysql> show processlist;
+----+------+-----------------+------+---------+------+----------+------------------+
| Id | User | Host            | db   | Command | Time | State    | Info             |
+----+------+-----------------+------+---------+------+----------+------------------+
|  3 | root | localhost:60989 | cmdb | Sleep   |  318 |          | NULL             |
|  4 | root | localhost:60990 | cmdb | Sleep   |  318 |          | NULL             |
| 15 | root | localhost       | NULL | Query   |    0 | starting | show processlist |
+----+------+-----------------+------+---------+------+----------+------------------+
3 rows in set (0.00 sec)

查看数据表information_schema.processlist:

mysql> select * from  information_schema.processlist;
+----+------+-----------------+------+---------+------+-----------+-----------------------------------------------+
| ID | USER | HOST            | DB   | COMMAND | TIME | STATE     | INFO                                          |
+----+------+-----------------+------+---------+------+-----------+-----------------------------------------------+
|  3 | root | localhost:60989 | cmdb | Sleep   |  157 |           | NULL                                          |
| 15 | root | localhost       | NULL | Query   |    0 | executing | select * from  INFORMATION_SCHEMA.PROCESSLIST |
|  4 | root | localhost:60990 | cmdb | Sleep   |  157 |           | NULL                                          |
+----+------+-----------------+------+---------+------+-----------+-----------------------------------------------+
3 rows in set (0.00 sec)

查看数据表performance_schema.threads：

mysql> select thread_id, name, processlist_id from performance_schema.threads;
+-----------+----------------------------------------+----------------+
| thread_id | name                                   | processlist_id |
+-----------+----------------------------------------+----------------+
|         1 | thread/sql/main                        |           NULL |
|         2 | thread/sql/thread_timer_notifier       |           NULL |
|         3 | thread/innodb/io_ibuf_thread           |           NULL |
|         4 | thread/innodb/io_log_thread            |           NULL |
|         5 | thread/innodb/io_read_thread           |           NULL |
|         6 | thread/innodb/io_read_thread           |           NULL |
|         7 | thread/innodb/io_read_thread           |           NULL |
|         8 | thread/innodb/io_read_thread           |           NULL |
|         9 | thread/innodb/io_write_thread          |           NULL |
|        10 | thread/innodb/io_write_thread          |           NULL |
|        11 | thread/innodb/io_write_thread          |           NULL |
|        12 | thread/innodb/io_write_thread          |           NULL |
|        13 | thread/innodb/page_cleaner_thread      |           NULL |
|        16 | thread/innodb/srv_lock_timeout_thread  |           NULL |
|        15 | thread/innodb/srv_error_monitor_thread |           NULL |
|        17 | thread/innodb/srv_monitor_thread       |           NULL |
|        18 | thread/innodb/srv_master_thread        |           NULL |
|        19 | thread/innodb/srv_worker_thread        |           NULL |
|        20 | thread/innodb/srv_worker_thread        |           NULL |
|        21 | thread/innodb/srv_purge_thread         |           NULL |
|        22 | thread/innodb/srv_worker_thread        |           NULL |
|        23 | thread/innodb/buf_dump_thread          |           NULL |
|        24 | thread/innodb/dict_stats_thread        |           NULL |
|        25 | thread/sql/signal_handler              |           NULL |
|        26 | thread/sql/compress_gtid_table         |              1 |
|        28 | thread/sql/one_connection              |              3 |
|        29 | thread/sql/one_connection              |              4 |
|        40 | thread/sql/one_connection              |             15 |
+-----------+----------------------------------------+----------------+
28 rows in set (0.00 sec)

参考

https://dev.mysql.com/doc/refman/5.7/en/information-functions.html

https://dev.mysql.com/doc/refman/5.7/en/threads-table.html