MySQL性能跟蹤語句教程
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1、不過版本要在5.0.37之后
手冊上介紹：(SHOW PROFILES and SHOW PROFILE were added in MySQL 5.0.37. )
Important
Please note that the SHOW PROFILE and SHOW PROFILES functionality is part of the MySQL 5.0 Community Server only.
2、變量profiling是用戶變量，每次都得重新啟用。
以下是我做的一些實驗。數據很明顯，就不多解釋了。
mysql> use test
Database changed
mysql> set profiling=1;
Query OK, 0 rows affected (0.00 sec)
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| bag_item |
| bag_user |
| score |
| t |
+----------------+
4 rows in set (0.03 sec)
mysql> select count(*) from t;
+----------+
| count(*) |
+----------+
| 2097152 |
+----------+
1 row in set (0.74 sec)
mysql> show profiles;
+----------+------------+------------------------+
| Query_ID | Duration | Query |
+----------+------------+------------------------+
| 1 | 0.02717000 | show tables |
| 2 | 0.74770100 | select count(*) from t |
+----------+------------+------------------------+
2 rows in set (0.00 sec)
mysql> show profile for query 2;
+--------------------------------+----------+
| Status | Duration |
+--------------------------------+----------+
| (initialization) | 0.000004 |
| checking query cache for query | 0.000044 |
| Opening tables | 0.000012 |
| System lock | 0.000017 |
| Table lock | 0.00003 |
| init | 0.000013 |
| optimizing | 0.000008 |
| statistics | 0.000013 |
| preparing | 0.000011 |
| executing | 0.000006 |
| Sending data | 0.747313 |
| end | 0.000014 |
| query end | 0.000006 |
| storing result in query cache | 0.000006 |
| freeing items | 0.000012 |
| closing tables | 0.000009 |
| logging slow query | 0.000183 |
+--------------------------------+----------+
17 rows in set (0.00 sec)
mysql> show profile block io,cpu for query 2;
+--------------------------------+----------+----------+------------+--------------+---------------+
| Status | Duration | CPU_user | CPU_system | Block_ops_in | Block_ops_out |
+--------------------------------+----------+----------+------------+--------------+---------------+
| (initialization) | 0.000004 | 0 | 0 | 0 | 0 |
| checking query cache for query | 0.000044 | 0 | 0 | 0 | 0 |
| Opening tables | 0.000012 | 0 | 0 | 0 | 0 |
| System lock | 0.000017 | 0 | 0 | 0 | 0 |
| Table lock | 0.00003 | 0 | 0 | 0 | 0 |
| init | 0.000013 | 0 | 0 | 0 | 0 |
| optimizing | 0.000008 | 0 | 0 | 0 | 0 |
| statistics | 0.000013 | 0 | 0 | 0 | 0 |
| preparing | 0.000011 | 0 | 0 | 0 | 0 |
| executing | 0.000006 | 0 | 0 | 0 | 0 |
| Sending data | 0.747313 | 0.746887 | 0 | 0 | 0 |
| end | 0.000014 | 0 | 0 | 0 | 0 |
| query end | 0.000006 | 0 | 0 | 0 | 0 |
| storing result in query cache | 0.000006 | 0 | 0 | 0 | 0 |
| freeing items | 0.000012 | 0 | 0 | 0 | 0 |
| closing tables | 0.000009 | 0 | 0 | 0 | 0 |
| logging slow query | 0.000183 | 0 | 0 | 0 | 0 |
+--------------------------------+----------+----------+------------+--------------+---------------+
17 rows in set (0.00 sec)
mysql> insert into t(username) select username from t;
Query OK, 2097152 rows affected (34.17 sec)
Records: 2097152 Duplicates: 0 Warnings: 0
mysql> show profiles;
+----------+-------------+------------------------------------------------+
| Query_ID | Duration | Query |
+----------+-------------+------------------------------------------------+
| 1 | 0.02717000 | show tables |
| 2 | 0.74770100 | select count(*) from t |
| 3 | 0.00004200 | show prifile for query 2 |
| 4 | 34.30410100 | insert into t(username) select username from t |
+----------+-------------+------------------------------------------------+
4 rows in set (0.00 sec)
mysql> show profile cpu,block io,memory,swaps for query 4;
+------------------------------+-----------+-----------+------------+--------------+---------------+-------+
| Status | Duration | CPU_user | CPU_system | Block_ops_in | Block_ops_out | Swaps |
+------------------------------+-----------+-----------+------------+--------------+---------------+-------+
| (initialization) | 0.000038 | 0 | 0 | 0 | 0 | 0 |
| checking permissions | 0.000016 | 0 | 0 | 0 | 0 | 0 |
| Opening tables | 0.000014 | 0 | 0 | 0 | 0 | 0 |
| System lock | 0.000007 | 0 | 0 | 0 | 0 | 0 |
| Table lock | 0.000013 | 0 | 0 | 0 | 0 | 0 |
| init | 0.000015 | 0 | 0 | 0 | 0 | 0 |
| optimizing | 0.000006 | 0 | 0 | 0 | 0 | 0 |
| statistics | 0.000012 | 0 | 0 | 0 | 0 | 0 |
| preparing | 0.000011 | 0 | 0 | 0 | 0 | 0 |
| Creating tmp table | 0.000029 | 0 | 0 | 0 | 0 | 0 |
| executing | 0.000005 | 0 | 0 | 0 | 0 | 0 |
| Copying to tmp table | 1.262877 | 1.24981 | 0.012998 | 0 | 0 | 0 |
| converting HEAP to MyISAM | 0.384814 | 0.187971 | 0.19797 | 0 | 0 | 0 |
| Copying to tmp table on disk | 1.417069 | 1.203817 | 0.191971 | 0 | 0 | 0 |
| Sending data | 31.104185 | 13.965877 | 0.843872 | 0 | 0 | 0 |
| end | 0.000017 | 0 | 0 | 0 | 0 | 0 |
| removing tmp table | 0.134872 | 0 | 0.029995 | 0 | 0 | 0 |
| end | 0.000026 | 0 | 0 | 0 | 0 | 0 |
| query end | 0.000006 | 0 | 0 | 0 | 0 | 0 |
| freeing items | 0.000011 | 0 | 0 | 0 | 0 | 0 |
| closing tables | 0.000009 | 0 | 0 | 0 | 0 | 0 |
| logging slow query | 0.000049 | 0 | 0 | 0 | 0 | 0 |
+------------------------------+-----------+-----------+------------+--------------+---------------+-------+
22 rows in set (0.00 sec)
mysql> select count(*) from t;
+----------+
| count(*) |
+----------+
| 4194304 |
+----------+
1 row in set (1.51 sec)
mysql> show profiles;
+----------+-------------+------------------------------------------------+
| Query_ID | Duration | Query |
+----------+-------------+------------------------------------------------+
| 1 | 0.02717000 | show tables |
| 2 | 0.74770100 | select count(*) from t |
| 3 | 0.00004200 | show prifile for query 2 |
| 4 | 34.30410100 | insert into t(username) select username from t |
| 5 | 1.50563800 | select count(*) from t |
+----------+-------------+------------------------------------------------+
5 rows in set (0.00 sec)
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