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Mysql必讀mysql顯示SQL語句執(zhí)行時間的實例詳解

作者：VEPHP   時間 2017-09-27

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導(dǎo)讀：本節(jié)內(nèi)容：顯示SQL語句執(zhí)行時間MySQL 的 SQL 語法調(diào)整主要使用 EXPLAIN,不過該命令無法獲取詳細(xì)的 Ram(Memory)/CPU 等使用量.于 My...

本節(jié)內(nèi)容：
顯示SQL語句執(zhí)行時間MYSQL教程

MySQL 的 SQL 語法調(diào)整主要使用 EXPLAIN,不過該命令無法獲取詳細(xì)的 Ram(Memory)/CPU 等使用量.MYSQL教程

于 MySQL 5.0.37 以上開始支持 MySQL Query Profiler, 可以查詢到此 SQL執(zhí)行多長時間,并 並看出 CPU/Memory 使用量, 執(zhí)行過程中 System lock, Table lock 花多少時間等.MYSQL教程

效能分析主要分下述三種:
Bottleneck analysis - focuses on answering the questions: What is my database server waiting on; what is a user connection waiting on; what is a piece of SQL code waiting on?MYSQL教程

Workload analysis - examines the server and who is logged on to determine the resource usage and activity of each.MYSQL教程

Ratio-based analysis - utilizes a number of rule-of-thumb ratios to gauge performance of a database, user connection, or piece of code.MYSQL教程

MySQL Query Profile 使用方法MYSQL教程

啟動：
mysql> set profiling=1; # 此命令于 MySQL 會于 information_schema 的 database 建立一個 PROFILING 的 table 來記錄.MYSQL教程

SQL profiles show
mysql> show profiles; # 從啟動之后所有語法及使用時間, 含錯誤語法都會記錄.
例如:MYSQL教程

(root@jbxue.com) [test]> show profiles; # 注意 Query_ID, 下面執(zhí)行時間統(tǒng)計等, 都是依 Query_ID 在記錄
+----------+------------+---------------------------+
| Query_ID | Duration?? | Query???????????????????? |
+----------+------------+---------------------------+
|??????? 1 | 0.00090400 | show profile for query 1? |
|??????? 2 | 0.00008700 | select * from users?????? |
|??????? 3 | 0.00183800 | show tables?????????????? |
|??????? 4 | 0.00027600 | mysql> show profiles????? |
+----------+------------+---------------------------+

1,查詢所有花費(fèi)時間加總
?MYSQL教程

mysql> select sum(duration) from information_schema.profiling where query_id=1; # Query ID = 1
+---------------+
| sum(duration) |
+---------------+
|????? 0.000447 |
+---------------+

2,查詢各執(zhí)行階段花費(fèi)多少時間
?MYSQL教程

mysql> show profile for query 1; # Query ID = 1
+--------------------+------------+
| Status???????????? | Duration?? |
+--------------------+------------+
| (initialization)?? | 0.00006300 |
| Opening tables???? | 0.00001400 |
| System lock??????? | 0.00000600 |
| Table lock???????? | 0.00001000 |
| init?????????????? | 0.00002200 |
| optimizing???????? | 0.00001100 |
| statistics???????? | 0.00009300 |
| preparing????????? | 0.00001700 |
| executing????????? | 0.00000700 |
| Sending data?????? | 0.00016800 |
| end??????????????? | 0.00000700 |
| query end????????? | 0.00000500 |
| freeing items????? | 0.00001200 |
| closing tables???? | 0.00000800 |
| logging slow query | 0.00000400 |
+--------------------+------------+

3,查詢各執(zhí)行階段花費(fèi)的各種資源列表
?MYSQL教程

mysql> show profile cpu for query 1; # Query ID = 1
+--------------------------------+----------+----------+------------+
| Status???????????????????????? | Duration | CPU_user | CPU_system |
+--------------------------------+----------+----------+------------+
| (initialization)?????????????? | 0.000007 | 0??????? | 0????????? |
| checking query cache for query | 0.000071 | 0??????? | 0????????? |
| Opening tables???????????????? | 0.000024 | 0??????? | 0????????? |
| System lock??????????????????? | 0.000014 | 0??????? | 0????????? |
| Table lock???????????????????? | 0.000055 | 0.001??? | 0????????? |
| init?????????????????????????? | 0.000036 | 0??????? | 0????????? |
| optimizing???????????????????? | 0.000013 | 0??????? | 0????????? |
| statistics???????????????????? | 0.000021 | 0??????? | 0????????? |
| preparing????????????????????? | 0.00002? | 0??????? | 0????????? |
| executing????????????????????? | 0.00001? | 0??????? | 0????????? |
| Sending data?????????????????? | 0.015072 | 0.011998 | 0????????? |
| end??????????????????????????? | 0.000021 | 0??????? | 0????????? |
| query end????????????????????? | 0.000011 | 0??????? | 0????????? |
| storing result in query cache? | 0.00001? | 0??????? | 0????????? |
| freeing items????????????????? | 0.000018 | 0??????? | 0????????? |
| closing tables???????????????? | 0.000019 | 0??????? | 0????????? |
| logging slow query???????????? | 0.000009 | 0??????? | 0????????? |
+--------------------------------+----------+----------+------------+MYSQL教程

mysql> show profile IPC for query 1;
+--------------------------------+----------+---------------+-------------------+
| Status???????????????????????? | Duration | Messages_sent | Messages_received |
+--------------------------------+----------+---------------+-------------------+
| (initialization)?????????????? | 0.000007 |???????????? 0 |???????????????? 0 |
| checking query cache for query | 0.000071 |???????????? 0 |???????????????? 0 |
| Opening tables???????????????? | 0.000024 |???????????? 0 |???????????????? 0 |
| System lock??????????????????? | 0.000014 |???????????? 0 |???????????????? 0 |
| Table lock???????????????????? | 0.000055 |???????????? 0 |???????????????? 0 |
| init?????????????????????????? | 0.000036 |???????????? 0 |???????????????? 0 |
| optimizing???????????????????? | 0.000013 |???????????? 0 |???????????????? 0 |
| statistics???????????????????? | 0.000021 |???????????? 0 |???????????????? 0 |
| preparing????????????????????? | 0.00002? |???????????? 0 |???????????????? 0 |
| executing????????????????????? | 0.00001? |???????????? 0 |???????????????? 0 |
| Sending data?????????????????? | 0.015072 |???????????? 0 |???????????????? 0 |
| end??????????????????????????? | 0.000021 |???????????? 0 |???????????????? 0 |
| query end????????????????????? | 0.000011 |???????????? 0 |???????????????? 0 |
| storing result in query cache? | 0.00001? |???????????? 0 |???????????????? 0 |
| freeing items????????????????? | 0.000018 |???????????? 0 |???????????????? 0 |
| closing tables???????????????? | 0.000019 |???????????? 0 |???????????????? 0 |
| logging slow query???????????? | 0.000009 |???????????? 0 |???????????????? 0 |
+--------------------------------+----------+---------------+-------------------+MYSQL教程

4,其它屬性列表
?MYSQL教程

ALL - displays all information
BLOCK IO - displays counts for block input and output operations
CONTEXT SWITCHES - displays counts for voluntary and involuntary context switches
IPC - displays counts for messages sent and received
MEMORY - is not currently implemented
PAGE FAULTS - displays counts for major and minor page faults
SOURCE - displays the names of functions from the source code, together with the name and line number of the file in which the function occurs
SWAPS - displays swap counts

5,設(shè)定 Profiling 存的 Size：
?MYSQL教程

mysql> show variables where variable_name='profiling_history_size'; # 預(yù)設(shè)是 15筆

關(guān)閉：
?MYSQL教程

mysql> set profiling=0;

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