MySQL中應用SHOW PROFILE敕令剖析機能的用法整頓。本站提示廣大學習愛好者：（MySQL中應用SHOW PROFILE敕令剖析機能的用法整頓）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中應用SHOW PROFILE敕令剖析機能的用法整頓正文
show profile是由Jeremy Cole募捐給MySQL社區版本的。默許的是封閉的，然則會話級別可以開啟這個功效。開啟它可讓MySQL搜集在履行語句的時刻所應用的資本。為了統計報表,把profiling設為1
mysql> SET profiling = 1;
以後在運轉一個查詢
mysql> SELECT COUNT(DISTINCT actor.first_name) AS cnt_name, COUNT(*) AS cnt -> FROM sakila.film_actor -> INNER JOIN sakila.actor USING(actor_id) -> GROUP BY sakila.film_actor.film_id -> ORDER BY cnt_name DESC; ... 997 rows in set (0.03 sec)
這個履行語句的分析信息存儲在這個會話中。應用SHOW PROFILES停止檢查。
mysql> SHOW PROFILES\G
*************************** 1. row *************************** Query_ID: 1 Duration: 0.02596900 Query: SELECT COUNT(DISTINCT actor.first_name) AS cnt_name,...
你可使用SHOW PROFILE語句來獲得曾經存儲的分析數據。假如不加參數，會顯示狀況和它們連續的時光。
mysql> SHOW PROFILE;
+------------------------+-----------+ | Status | Duration | +------------------------+-----------+ | (initialization) | 0.000005 | | Opening tables | 0.000033 | | System lock | 0.000037 | | Table lock | 0.000024 | | init | 0.000079 | | optimizing | 0.000024 | | statistics | 0.000079 | | preparing | 0.00003 | | Creating tmp table | 0.000124 | | executing | 0.000008 | | Copying to tmp table | 0.010048 | | Creating sort index | 0.004769 | | Copying to group table | 0.0084880 | | Sorting result | 0.001136 | | Sending data | 0.000925 | | end | 0.00001 | | removing tmp table | 0.00004 | | end | 0.000005 | | removing tmp table | 0.00001 | | end | 0.000011 | | query end | 0.00001 | | freeing items | 0.000025 | | removing tmp table | 0.00001 | | freeing items | 0.000016 | | closing tables | 0.000017 | | logging slow query | 0.000006 | +------------------------+-----------+
每行都是狀況變更的進程和它們連續的時光。Status那一列和SHOW FULL PROCESSLIST的State應當是分歧的。
這個值是來自於thd->proc_info變量。是以你所檢查的這個值是直接來自MySQL外部的。雖然這些數值是比擬直接易懂的，你也能夠檢查MySQL手冊。
你可以給SHOW PROFILES指定一個Query_ID來檢查指定的語句，還可以給輸入添加新的列。如，檢查用戶和CPU應用。可以用以下敕令。
mysql> SHOW PROFILE CPU FOR QUERY 1;
SHOW PROFILE可以深刻的檢查辦事器履行語句的任務情形。和也能贊助你懂得履行語句消費時光的情形。一些限制是它沒有完成的功效，不克不及檢查和分析其他銜接的語句，和分析時所惹起的消費。
SHOW PROFILES顯示比來發給辦事器的多條語句，條數依據會話變量profiling_history_size界說，默許是15，最年夜值為100。設為0等價於封閉剖析功效。
SHOW PROFILE FOR QUERY n，這裡的n就是對應SHOW PROFILES輸入中的Query_ID。
例如：
mysql> show profiles;
+----------+-------------+---------------------------------------+ | Query_ID | Duration | Query | +----------+-------------+---------------------------------------+ | 1 | 0.00037700 | alter table table1 drop column c3 int | | 2 | 70.37123800 | alter table table1 drop column c3 | | 3 | 0.00124500 | show tables | | 4 | 0.00569800 | select * from table1 where id=2 | | 5 | 0.00068500 | select count(1) from tables1 | | 6 | 0.00197900 | select count(1) from table1 | | 7 | 0.00105900 | alter table tables1 drop c1 | | 8 | 0.00800200 | alter table table1 drop c1 | +----------+-------------+---------------------------------------+ 8 rows in set (0.00 sec)
mysql> SHOW PROFILE FOR QUERY 2; #檢查alter table table1 drop column c3的剖析
+------------------------------+-----------+ | Status | Duration | +------------------------------+-----------+ | starting | 0.000183 | | checking permissions | 0.000057 | | checking permissions | 0.000059 | | init | 0.000060 | | Opening tables | 0.000071 | | System lock | 0.000062 | | setup | 0.000080 | | creating table | 0.005052 | | After create | 0.000220 | | copy to tmp table | 0.000244 | | rename result table | 70.364027 | | end | 0.000575 | | Waiting for query cache lock | 0.000062 | | end | 0.000075 | | query end | 0.000057 | | closing tables | 0.000061 | | freeing items | 0.000080 | | logging slow query | 0.000056 | | logging slow query | 0.000098 | | cleaning up | 0.000059 | +------------------------------+-----------+ 20 rows in set (0.00 sec)
假如沒有指定FOR QUERY，那末輸入比來一條語句的信息。
LIMIT部門的用法與SELECT中LIMIT子句分歧，不贅述。
type是可選的，取值規模可以以下：
例：
mysql> show profile cpu for query 2;
+------------------------------+-----------+----------+------------+ | Status | Duration | CPU_user | CPU_system | +------------------------------+-----------+----------+------------+ | starting | 0.000183 | 0.000000 | 0.000000 | | checking permissions | 0.000057 | 0.000000 | 0.000000 | | checking permissions | 0.000059 | 0.000000 | 0.000000 | | init | 0.000060 | 0.000000 | 0.000000 | | Opening tables | 0.000071 | 0.000000 | 0.000000 | | System lock | 0.000062 | 0.000000 | 0.000000 | | setup | 0.000080 | 0.000000 | 0.001000 | | creating table | 0.005052 | 0.003000 | 0.001000 | | After create | 0.000220 | 0.000000 | 0.000000 | | copy to tmp table | 0.000244 | 0.000000 | 0.000000 | | rename result table | 70.364027 | 7.470864 | 41.612674 | | end | 0.000575 | 0.000000 | 0.001000 | | Waiting for query cache lock | 0.000062 | 0.000000 | 0.000000 | | end | 0.000075 | 0.000000 | 0.000000 | | query end | 0.000057 | 0.000000 | 0.000000 | | closing tables | 0.000061 | 0.000000 | 0.000000 | | freeing items | 0.000080 | 0.000000 | 0.000000 | | logging slow query | 0.000056 | 0.000000 | 0.000000 | | logging slow query | 0.000098 | 0.000000 | 0.000000 | | cleaning up | 0.000059 | 0.000000 | 0.000000 | +------------------------------+-----------+----------+------------+ 20 rows in set (0.00 sec)
ps:
SHOW PROFILE ALL FOR QUERY 2;的信息還可以經由過程SELECT * FROM information_schema.profiling WHERE query_id = 2 ORDER BY seq;獲得。
感化規模
這個敕令只是在本會話內起感化，即沒法剖析本會話外的語句。
開啟剖析功效後，一切本會話中的語句都被剖析（乃至包含履行毛病的語句），除SHOW PROFILE和SHOW PROFILES兩句自己。
運用示例：應用SHOW PROFILE剖析查詢緩存射中的機能優勢。
mysql> set profiling=1;
Query OK, 0 rows affected (0.00 sec)
mysql> select count(1) as cnt from tran_excution;
+-------+ | cnt | +-------+ | 14225 | +-------+ 1 row in set (0.00 sec)
因為曾經啟用了查詢緩存，雷同查詢（非分區表）可以直接在查詢緩存中射中。
mysql> select count(1) as cnt from tran_excution;
我們細心看下兩個異樣的語句的剖析。
mysql> show profile source for query 1;
+--------------------------------+----------+-----------------------+---------------+-------------+ | Status | Duration | Source_function | Source_file | Source_line | +--------------------------------+----------+-----------------------+---------------+-------------+ | starting | 0.000048 | NULL | NULL | NULL | | Waiting for query cache lock | 0.000013 | try_lock | sql_cache.cc | 454 | | checking query cache for query | 0.000040 | send_result_to_client | sql_cache.cc | 1561 | | checking permissions | 0.000023 | check_access | sql_parse.cc | 4751 | | Opening tables | 0.000040 | open_tables | sql_base.cc | 4831 | | System lock | 0.000020 | mysql_lock_tables | lock.cc | 299 | | Waiting for query cache lock | 0.000037 | try_lock | sql_cache.cc | 454 | | init | 0.000020 | mysql_select | sql_select.cc | 2579 | | optimizing | 0.000015 | optimize | sql_select.cc | 865 | | statistics | 0.000017 | optimize | sql_select.cc | 1056 | | preparing | 0.000016 | optimize | sql_select.cc | 1078 | | executing | 0.000015 | exec | sql_select.cc | 1836 | | Sending data | 0.003875 | exec | sql_select.cc | 2380 | | end | 0.000018 | mysql_select | sql_select.cc | 2615 | | query end | 0.000015 | mysql_execute_command | sql_parse.cc | 4440 | | closing tables | 0.000016 | mysql_execute_command | sql_parse.cc | 4492 | | freeing items | 0.000016 | mysql_parse | sql_parse.cc | 5640 | | Waiting for query cache lock | 0.000012 | try_lock | sql_cache.cc | 454 | | freeing items | 0.000032 | NULL | NULL | NULL | | Waiting for query cache lock | 0.000017 | try_lock | sql_cache.cc | 454 | | freeing items | 0.000016 | NULL | NULL | NULL | | storing result in query cache | 0.000017 | end_of_result | sql_cache.cc | 1020 | | logging slow query | 0.000018 | log_slow_statement | sql_parse.cc | 1461 | | logging slow query | 0.000050 | log_slow_statement | sql_parse.cc | 1470 | | cleaning up | 0.000018 | dispatch_command | sql_parse.cc | 1417 | +--------------------------------+----------+-----------------------+---------------+-------------+ 25 rows in set (0.00 sec)
mysql> show profile source for query 2;
+--------------------------------+----------+-----------------------+--------------+-------------+ | Status | Duration | Source_function | Source_file | Source_line | +--------------------------------+----------+-----------------------+--------------+-------------+ | starting | 0.000051 | NULL | NULL | NULL | | Waiting for query cache lock | 0.000014 | try_lock | sql_cache.cc | 454 | | checking query cache for query | 0.000016 | send_result_to_client | sql_cache.cc | 1561 | | checking privileges on cached | 0.000013 | send_result_to_client | sql_cache.cc | 1652 | | checking permissions | 0.000015 | check_access | sql_parse.cc | 4751 | | sending cached result to clien | 0.000036 | send_result_to_client | sql_cache.cc | 1749 | | logging slow query | 0.000017 | log_slow_statement | sql_parse.cc | 1461 | | cleaning up | 0.000018 | dispatch_command | sql_parse.cc | 1417 | +--------------------------------+----------+-----------------------+--------------+-------------+ 8 rows in set (0.00 sec)
可以清楚地看到緩存中射中時，年夜年夜節儉了後台的開支。固然緩存的應用也須要依據各類場景（表的數據范圍，更新頻率等）考核應用，其實不是啟用緩存就必定可以或許進步查詢效力。這裡僅僅作為SHOW PROFILE的一個運用示例。
