MySQL 分析

Question

在 MySQL 中可以使用 SET profiling = 1;

设置分析

查询 SHOW PROFILES; 显示每个查询所用的时间。我想知道这个时间是只包括服务器的执行时间还是还包括将结果发送到前端所花费的时间。

谢谢

Answer 1

根据manual state Sending data 是将结果发送到客户端所花费的时间。示例:

mysql> SHOW PROFILE FOR QUERY 1;
+--------------------------------+----------+
| Status                         | Duration |
+--------------------------------+----------+
| starting                       | 0.000024 |
| Waiting for query cache lock   | 0.000005 |
| checking query cache for query | 0.000051 |
| checking permissions           | 0.000010 |
| Opening tables                 | 0.000022 |
| System lock                    | 0.000012 |
| Waiting for query cache lock   | 0.000024 |
| init                           | 0.000043 |
| optimizing                     | 0.000008 |
| statistics                     | 0.000012 |
| preparing                      | 0.000011 |
| executing                      | 0.000004 |
| Sorting result                 | 0.125893 |
| Sending data                   | 0.000076 | -- here
| end                            | 0.000005 |
| query end                      | 0.000002 |
| closing tables                 | 0.000005 |
| freeing items                  | 0.000005 |
| Waiting for query cache lock   | 0.000001 |
| freeing items                  | 0.000012 |
| Waiting for query cache lock   | 0.000001 |
| freeing items                  | 0.000001 |
| storing result in query cache  | 0.000013 |
| logging slow query             | 0.000001 |
| cleaning up                    | 0.000002 |
+--------------------------------+----------+

更新:在使用查询缓存时，状态可能是正在向客户端发送缓存结果。