MySQL 显示SQL执行时间
1.环境
OS: CentOS 6.5 x64
MySQL: 5.6 for Linux (x86_64)
2.打开profiling
打开profiling可以统计资源统计功能。
mysql> set profiling=1; #打开profiling
Query OK, 0 rows affected, 1 warning (0.07 sec)
mysql> select count(*) from emp;
+----------+
| count(*) |
+----------+
| 14 |
+----------+
1 row in set (0.05 sec)
mysql> show profile; #显示最近执行的SQL的统计信息
+----------------------+----------+
| Status | Duration |
+----------------------+----------+
| starting | 0.052905 |
| checking permissions | 0.004080 |
| Opening tables | 0.000037 |
| init | 0.000025 |
| System lock | 0.000018 |
| optimizing | 0.000010 |
| statistics | 0.000021 |
| preparing | 0.000017 |
| executing | 0.000006 |
| Sending data | 0.000057 |
| end | 0.000012 |
| query end | 0.000013 |
| closing tables | 0.000013 |
| freeing items | 0.000287 |
| cleaning up | 0.000021 |
+----------------------+----------+
15 rows in set, 1 warning (0.09 sec)
mysql> show profiles; #显示最近执行的SQL列表，默认最多只能显示15条，可以通过修改profiling_history_size进行调整
+----------+------------+--------------------------+
| Query_ID | Duration | Query |
+----------+------------+--------------------------+
| 1 | 0.05752050 | select count(*) from emp |
+----------+------------+--------------------------+
1 row in set, 1 warning (0.02 sec)
#有一个报警
mysql> show warnings;
+---------+------+--------------------------------------------------------------------------------------------------------------+
| Level | Code | Message |
+---------+------+--------------------------------------------------------------------------------------------------------------+
| Warning | 1287 | 'SHOW PROFILES' is deprecated and will be removed in a future release. Please use Performance Schema instead |
+---------+------+--------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
#显示show profiles这样的命令即将过期不再补支持，应该通过Performance Schema进行查询
mysql> use information_schema
Database changed
mysql> SELECT STATE, FORMAT(DURATION, 6) AS DURATION
-> FROM INFORMATION_SCHEMA.PROFILING
-> WHERE QUERY_ID = 2 ORDER BY SEQ;
可以这样查询，但内容不如show profile(s)直观。
mysql> select count(*) from bt; #再执行一句，这是大表
+----------+
| count(*) |
+----------+
| 47927530 |
+----------+
1 row in set (1 min 49.18 sec)
mysql> show profile; #显示最近SQL的统计信息
+----------------------+------------+
| Status | Duration |
+----------------------+------------+
| starting | 0.000184 |
| checking permissions | 0.000020 |
| Opening tables | 0.000030 |
| init | 0.000053 |
| System lock | 0.000019 |
| optimizing | 0.000013 |
| statistics | 0.000023 |
| preparing | 0.000021 |
| executing | 0.000007 |
| Sending data | 109.159082 | #由于是大表，这一步花了109秒多
| end | 0.029567 |
| query end | 0.011552 |
| closing tables | 0.000044 |
| freeing items | 0.000623 |
| logging slow query | 0.000016 |
| cleaning up | 0.000026 |
+----------------------+------------+
16 rows in set, 1 warning (0.21 sec)
mysql> show profiles; #看一下现在的语句列表，有两条了
+----------+--------------+--------------------------+
| Query_ID | Duration | Query |
+----------+--------------+--------------------------+
| 1 | 0.02656275 | select count(*) from emp |
| 2 | 108.16862700 | select count(*) from bt |
+----------+--------------+--------------------------+
2 rows in set, 1 warning (0.10 sec)
mysql> show profile for query 1; #如果想看第一条SQL的统计信息，就可以这样查询
+----------------------+----------+
| Status | Duration |
+----------------------+----------+
| starting | 0.000332 |
| checking permissions | 0.000031 |
| Opening tables | 0.000044 |
| init | 0.000046 |
| System lock | 0.000032 |
| optimizing | 0.000019 |
| statistics | 0.000036 |
| preparing | 0.000037 |
| executing | 0.000011 |
| Sending data | 0.025856 |
| end | 0.000039 |
| query end | 0.000016 |
| closing tables | 0.000019 |
| freeing items | 0.000028 |
| cleaning up | 0.000018 |
+----------------------+----------+
15 rows in set, 1 warning (0.08 sec)
3.profiling语法
show profile有许多选项，且看语法：
SHOW PROFILE [这些选项的意义如下：type[,type] ... ] [FOR QUERYn] [LIMITrow_count[OFFSEToffset]]type: ALL | BLOCK IO | CONTEXT SWITCHES | CPU | IPC | MEMORY | PAGE FAULTS | SOURCE | SWAPS
-
ALLdisplays all information -
BLOCK IOdisplays counts for block input and output operations -
CONTEXT SWITCHESdisplays counts for voluntary and involuntary context switches -
CPUdisplays user and system CPU usage times -
IPCdisplays counts for messages sent and received -
MEMORYis not currently implemented -
PAGE FAULTSdisplays counts for major and minor page faults -
SOURCEdisplays the names of functions from the source code, together with the name and line number of the file in which the function occurs -
SWAPSdisplays swap counts
mysql> show profile block io,cpu for query 2; #查看第二条SQL的block io和cpu信息
+----------------------+------------+-----------+------------+--------------+---------------+
| Status | Duration | CPU_user | CPU_system | Block_ops_in | Block_ops_out |
+----------------------+------------+-----------+------------+--------------+---------------+
| starting | 0.000245 | 0.000000 | 0.000000 | 0 | 0 |
| checking permissions | 0.000030 | 0.000000 | 0.000000 | 0 | 0 |
| Opening tables | 0.000042 | 0.000000 | 0.000000 | 0 | 0 |
| init | 0.000074 | 0.000000 | 0.000000 | 0 | 0 |
| System lock | 0.000030 | 0.000000 | 0.000000 | 0 | 0 |
| optimizing | 0.000019 | 0.000000 | 0.000000 | 0 | 0 |
| statistics | 0.000032 | 0.000000 | 0.000000 | 0 | 0 |
| preparing | 0.000029 | 0.000000 | 0.000000 | 0 | 0 |
| executing | 0.000010 | 0.000000 | 0.000000 | 0 | 0 |
| Sending data | 108.126421 | 33.258944 | 3.981394 | 6507176 | 0 |
| end | 0.029766 | 0.001000 | 0.000000 | 424 | 0 |
| query end | 0.011333 | 0.001000 | 0.000000 | 208 | 0 |
| closing tables | 0.000041 | 0.000000 | 0.000000 | 0 | 0 |
| freeing items | 0.000519 | 0.000000 | 0.000000 | 0 | 0 |
| logging slow query | 0.000014 | 0.000000 | 0.000000 | 0 | 0 |
| cleaning up | 0.000023 | 0.000000 | 0.000000 | 0 | 0 |
+----------------------+------------+-----------+------------+--------------+---------------+
16 rows in set, 1 warning (0.00 sec)
会话退出后，profiling信息自动清空。