MySQL機能剖析對象profile應用教程。本站提示廣大學習愛好者：（MySQL機能剖析對象profile應用教程）文章只能為提供參考，不一定能成為您想要的結果。以下是MySQL機能剖析對象profile應用教程正文
剖析SQL履行帶來的開支是優化SQL的主要手腕。在MySQL數據庫中，可以經由過程設置裝備擺設profiling參數來啟用SQL分析。該參數可以在全局和session級別來設置。關於全局級別則感化於全部MySQL實例，而session級別緊影響以後session。該參數開啟後，後續履行的SQL語句都將記載其資本開支，諸如IO，高低文切換，CPU，Memory等等。依據這些開支進一步剖析以後SQL瓶頸從而停止優化與調劑。本文描寫了若何應用MySQL profile，不觸及詳細的樣例剖析。
1、有關profile的描寫
--以後版本
root@localhost[sakila]> show variables like 'version';
+---------------+---------------------------------------+
| Variable_name | Value |
+---------------+---------------------------------------+
| version | 5.6.17-enterprise-commercial-advanced |
+---------------+---------------------------------------+
--檢查profiling體系變量
root@localhost[sakila]> show variables like '%profil%';
+------------------------+-------+
| Variable_name | Value |
+------------------------+-------+
| have_profiling | YES | --只讀變量，用於掌握能否由體系變量開啟或禁用profiling
| profiling | OFF | --開啟SQL語句分析功效
| profiling_history_size | 15 | --設置保存profiling的數量，缺省為15，規模為0至100，為0時將禁用profiling
+------------------------+-------+
profiling [539]
If set to 0 or OFF (the default), statement profiling is disabled. If set to 1 or ON, statement prof
is enabled and the SHOW PROFILE and SHOW PROFILES statements provide access to prof
information. See Section 13.7.5.32, “SHOW PROFILES Syntax”.
This variable is deprecated in MySQL 5.6.8 and will be removed in a future MySQL release.
profiling_history_size [539]
The number of statements for which to maintain profiling information if profiling [539] is
enabled. The default value is 15. The maximum value is 100. Setting the value to 0 effectively
disables profiling. See Section 13.7.5.32, “SHOW PROFILES Syntax”.
This variable is deprecated in MySQL 5.6.8 and will be removed in a future MySQL release.
--獲得profile的贊助
root@localhost[sakila]> help profile;
Name: 'SHOW PROFILE'
Description:
Syntax:
SHOW PROFILE [type [, type] ... ]
[FOR QUERY n]
[LIMIT row_count [OFFSET offset]]
type:
ALL --顯示一切的開支信息
| BLOCK IO --顯示塊IO相干開支
| CONTEXT SWITCHES --高低文切換相干開支
| CPU --顯示CPU相干開支信息
| IPC --顯示發送和吸收相干開支信息
| MEMORY --顯示內存相干開支信息
| PAGE FAULTS --顯示頁面毛病相干開支信息
| SOURCE --顯示和Source_function，Source_file，Source_line相干的開支信息
| SWAPS --顯示交流次數相干開支的信息
The SHOW PROFILE and SHOW PROFILES statements display profiling
information that indicates resource usage for statements executed
during the course of the current session.
*Note*: These statements are deprecated as of MySQL 5.6.7 and will be
removed in a future MySQL release. Use the Performance Schema instead;
see http://dev.mysql.com/doc/refman/5.6/en/performance-schema.html.
--下面描寫從5.6.7開端該敕令將會被移除，用Performance Schema instead取代
--在Oracle數據庫中，是經由過程autotrace來分析單條SQL並獲得真實的履行籌劃和其開支信息
2、開啟porfiling
--啟用session級其余profiling
root@localhost[sakila]> set profiling=1;
Query OK, 0 rows affected, 1 warning (0.00 sec)
--驗證修正後的成果
root@localhost[sakila]> show variables like '%profil%';
+------------------------+-------+
| Variable_name | Value |
+------------------------+-------+
| have_profiling | YES |
| profiling | ON |
| profiling_history_size | 15 |
+------------------------+-------+
--宣布SQL查詢
root@localhost[sakila]> select count(*) from customer;
+----------+
| count(*) |
+----------+
| 599 |
+----------+
--檢查以後session一切已發生的profile
root@localhost[sakila]> show profiles;
+----------+------------+--------------------------------+
| Query_ID | Duration | Query |
+----------+------------+--------------------------------+
| 1 | 0.00253600 | show variables like '%profil%' |
| 2 | 0.00138150 | select count(*) from customer |
+----------+------------+--------------------------------+
2 rows in set, 1 warning (0.01 sec)
--我們看到有2個warning，之前一個，如今一個
root@localhost[sakila]> show warnings; --上面的成果注解SHOW PROFILES未來會被Performance Schema調換失落
+---------+------+--------------------------------------------------------------------------------------------------------------+
| Level | Code | Message |
+---------+------+--------------------------------------------------------------------------------------------------------------+
| Warning | 1287 | 'SHOW PROFILES' is deprecated and will be removed in a future release. Please use Performance Schema instead |
+---------+------+--------------------------------------------------------------------------------------------------------------+
3、獲得SQL語句的開支信息
--可以直接應用show profile來檢查上一條SQL語句的開支信息
--注，show profile之類的語句不會被profiling，即本身不會發生Profiling
--我們上面的這個show profile檢查的是show warnings發生的響應開支
root@localhost[sakila]> show profile;
+----------------+----------+
| Status | Duration |
+----------------+----------+
| starting | 0.000141 |
| query end | 0.000058 |
| closing tables | 0.000014 |
| freeing items | 0.001802 |
| cleaning up | 0.000272 |
+----------------+----------+
--以下面的查詢show warnings被添加到profiles
root@localhost[sakila]> show profiles;
+----------+------------+--------------------------------+
| Query_ID | Duration | Query |
+----------+------------+--------------------------------+
| 1 | 0.00253600 | show variables like '%profil%' |
| 2 | 0.00138150 | select count(*) from customer |
| 3 | 0.00228600 | show warnings |
+----------+------------+--------------------------------+
--獲得指定查詢的開支
root@localhost[sakila]> show profile for query 2;
+----------------------+----------+
| Status | Duration |
+----------------------+----------+
| starting | 0.000148 |
| checking permissions | 0.000014 |
| Opening tables | 0.000047 |
| init | 0.000023 |
| System lock | 0.000035 |
| optimizing | 0.000012 |
| statistics | 0.000019 |
| preparing | 0.000014 |
| executing | 0.000006 |
| Sending data | 0.000990 |
| end | 0.000010 |
| query end | 0.000011 |
| closing tables | 0.000010 |
| freeing items | 0.000016 |
| cleaning up | 0.000029 |
+----------------------+----------+
--檢查特定部門的開支，以下為CPU部門的開支
root@localhost[sakila]> show profile cpu for query 2 ;
+----------------------+----------+----------+------------+
| Status | Duration | CPU_user | CPU_system |
+----------------------+----------+----------+------------+
| starting | 0.000148 | 0.000000 | 0.000000 |
| checking permissions | 0.000014 | 0.000000 | 0.000000 |
| Opening tables | 0.000047 | 0.000000 | 0.000000 |
| init | 0.000023 | 0.000000 | 0.000000 |
| System lock | 0.000035 | 0.000000 | 0.000000 |
| optimizing | 0.000012 | 0.000000 | 0.000000 |
| statistics | 0.000019 | 0.000000 | 0.000000 |
| preparing | 0.000014 | 0.000000 | 0.000000 |
| executing | 0.000006 | 0.000000 | 0.000000 |
| Sending data | 0.000990 | 0.001000 | 0.000000 |
| end | 0.000010 | 0.000000 | 0.000000 |
| query end | 0.000011 | 0.000000 | 0.000000 |
| closing tables | 0.000010 | 0.000000 | 0.000000 |
| freeing items | 0.000016 | 0.000000 | 0.000000 |
| cleaning up | 0.000029 | 0.000000 | 0.000000 |
+----------------------+----------+----------+------------+
--以下為MEMORY部門的開支
root@localhost[sakila]> show profile memory for query 2 ;
+----------------------+----------+
| Status | Duration |
+----------------------+----------+
| starting | 0.000148 |
| checking permissions | 0.000014 |
| Opening tables | 0.000047 |
| init | 0.000023 |
| System lock | 0.000035 |
| optimizing | 0.000012 |
| statistics | 0.000019 |
| preparing | 0.000014 |
| executing | 0.000006 |
| Sending data | 0.000990 |
| end | 0.000010 |
| query end | 0.000011 |
| closing tables | 0.000010 |
| freeing items | 0.000016 |
| cleaning up | 0.000029 |
+----------------------+----------+
--同時檢查分歧資本開支
root@localhost[sakila]> show profile block io,cpu for query 2;
+----------------------+----------+----------+------------+--------------+---------------+
| Status | Duration | CPU_user | CPU_system | Block_ops_in | Block_ops_out |
+----------------------+----------+----------+------------+--------------+---------------+
| starting | 0.000148 | 0.000000 | 0.000000 | 0 | 0 |
| checking permissions | 0.000014 | 0.000000 | 0.000000 | 0 | 0 |
| Opening tables | 0.000047 | 0.000000 | 0.000000 | 0 | 0 |
| init | 0.000023 | 0.000000 | 0.000000 | 0 | 0 |
| System lock | 0.000035 | 0.000000 | 0.000000 | 0 | 0 |
| optimizing | 0.000012 | 0.000000 | 0.000000 | 0 | 0 |
| statistics | 0.000019 | 0.000000 | 0.000000 | 0 | 0 |
| preparing | 0.000014 | 0.000000 | 0.000000 | 0 | 0 |
| executing | 0.000006 | 0.000000 | 0.000000 | 0 | 0 |
| Sending data | 0.000990 | 0.001000 | 0.000000 | 0 | 0 |
| end | 0.000010 | 0.000000 | 0.000000 | 0 | 0 |
| query end | 0.000011 | 0.000000 | 0.000000 | 0 | 0 |
| closing tables | 0.000010 | 0.000000 | 0.000000 | 0 | 0 |
| freeing items | 0.000016 | 0.000000 | 0.000000 | 0 | 0 |
| cleaning up | 0.000029 | 0.000000 | 0.000000 | 0 | 0 |
+----------------------+----------+----------+------------+--------------+---------------+
--上面的SQL語句用於查詢query_id為2的SQL開支，且按最年夜耗用時光倒序分列
root@localhost[sakila]> set @query_id=2;
root@localhost[sakila]> SELECT STATE, SUM(DURATION) AS Total_R,
-> ROUND(
-> 100 * SUM(DURATION) /
-> (SELECT SUM(DURATION)
-> FROM INFORMATION_SCHEMA.PROFILING
-> WHERE QUERY_ID = @query_id
-> ), 2) AS Pct_R,
-> COUNT(*) AS Calls,
-> SUM(DURATION) / COUNT(*) AS "R/Call"
-> FROM INFORMATION_SCHEMA.PROFILING
-> WHERE QUERY_ID = @query_id
-> GROUP BY STATE
-> ORDER BY Total_R DESC;
+----------------------+----------+-------+-------+--------------+
| STATE | Total_R | Pct_R | Calls | R/Call |
+----------------------+----------+-------+-------+--------------+
| Sending data | 0.000990 | 71.53 | 1 | 0.0009900000 |--最年夜耗用時光部門為發送數據
| starting | 0.000148 | 10.69 | 1 | 0.0001480000 |
| Opening tables | 0.000047 | 3.40 | 1 | 0.0000470000 |
| System lock | 0.000035 | 2.53 | 1 | 0.0000350000 |
| cleaning up | 0.000029 | 2.10 | 1 | 0.0000290000 |
| init | 0.000023 | 1.66 | 1 | 0.0000230000 |
| statistics | 0.000019 | 1.37 | 1 | 0.0000190000 |
| freeing items | 0.000016 | 1.16 | 1 | 0.0000160000 |
| preparing | 0.000014 | 1.01 | 1 | 0.0000140000 |
| checking permissions | 0.000014 | 1.01 | 1 | 0.0000140000 |
| optimizing | 0.000012 | 0.87 | 1 | 0.0000120000 |
| query end | 0.000011 | 0.79 | 1 | 0.0000110000 |
| end | 0.000010 | 0.72 | 1 | 0.0000100000 |
| closing tables | 0.000010 | 0.72 | 1 | 0.0000100000 |
| executing | 0.000006 | 0.43 | 1 | 0.0000060000 |
+----------------------+----------+-------+-------+--------------+
--開啟profiling後，我們可以經由過程show profile等方法檢查，其本質是這些開支信息被記載到information_schema.profiling表
--以下面的查詢，部門信息省略
profiling
root@localhost[information_schema]> select * from profiling limit 3,3\G;
*************************** 1. row ***************************
QUERY_ID: 1
SEQ: 5
STATE: init
DURATION: 0.000020
CPU_USER: 0.000000
CPU_SYSTEM: 0.000000
CONTEXT_VOLUNTARY: 0
CONTEXT_INVOLUNTARY: 0
BLOCK_OPS_IN: 0
BLOCK_OPS_OUT: 0
MESSAGES_SENT: 0
MESSAGES_RECEIVED: 0
PAGE_FAULTS_MAJOR: 0
PAGE_FAULTS_MINOR: 0
SWAPS: 0
SOURCE_FUNCTION: mysql_prepare_select
SOURCE_FILE: sql_select.cc
SOURCE_LINE: 1050
--停滯profile,可以設置profiling參數，或許在session加入以後,profiling會被主動封閉
root@localhost[sakila]> set profiling=off;
Query OK, 0 rows affected, 1 warning (0.00 sec)
