mysql \u7684 sql \u6548\u80fd\u5206\u6790\u5668\u4e3b\u8981\u7528\u9014\u662f\u986f\u793a sql \u57f7\u884c\u7684\u6574\u500b\u904e\u7a0b\u4e2d\u5404\u9805\u8cc7\u6e90\u7684\u4f7f\u7528\u60c5\u6cc1\u3002\u5206\u6790\u5668\u53ef\u4ee5\u66f4\u597d\u7684\u5c55\u793a\u51fa\u4e0d\u826f SQL \u7684\u6548\u80fd\u554f\u984c\u6240\u5728\u3002
\u4e0b\u9762\u6211\u5011\u8209\u4f8b\u4ecb\u7d39\u4e00\u4e0b MySQL SQL Profiler \u7684\u4f7f\u7528\u65b9\u6cd5\uff1a <\/p>\n
mysql> SELECT @@profiling;
+————-+
| @@profiling |
+————-+
| 0 |
+————-+
1 row in set (0.00 sec)
mysql> SET profiling = 1;
Query OK, 0 rows affected (0.00 sec)
mysql> SELECT @@profiling;
+————-+
| @@profiling |
+————-+
| 1 |
+————-+
1 row in set (0.00 sec)
\u9810\u8a2d\u60c5\u6cc1\u4e0b profiling \u7684\u503c\u70ba 0 \u8868\u793a MySQL SQL Profiler \u8655\u65bc OFF \u72c0\u614b\uff0c\u958b\u555f SQL \u6548\u80fd\u5206\u6790\u5668\u5f8c profiling \u7684\u503c\u70ba 1. <\/p>\n
mysql> create table t_engines select * from t_engines1;
Query OK, 57344 rows affected (0.10 sec)
Records: 57344 Duplicates: 0 Warnings: 0
mysql> select count(*) from t_engines;
+———-+
| count(*) |
+———-+
| 57344 |
+———-+
1 row in set (0.00 sec)
mysql> select count(*) from t_engines;
+———-+
| count(*) |
+———-+
| 57344 |
+———-+
1 row in set (0.00 sec)
mysql> SHOW PROFILES;
+———-+————+————————————————-+
| Query_ID | Duration | Query |
+———-+————+————————————————-+
| 26 | 0.10213775 | create table t_engines select * from t_engines1 |
| 27 | 0.00032775 | select count(*) from t_engines |
| 28 | 0.00003850 | select count(*) from t_engines |
+———-+————+————————————————-+
15 rows in set (0.01 sec)
mysql> SHOW PROFILE FOR QUERY 27;
+——————————–+————+
| Status | Duration |
+——————————–+————+
| (initialization) | 0.00000425 |
| checking query cache for query | 0.00004050 |
| checking permissions | 0.00001050 |
| Opening tables | 0.00018250 |
| System lock | 0.00000450 |
| Table lock | 0.00001775 |
| init | 0.00001075 |
| optimizing | 0.00000550 |
| executing | 0.00002775 |
| end | 0.00000450 |
| query end | 0.00000325 |
| storing result in query cache | 0.00000400 |
| freeing items | 0.00000400 |
| closing tables | 0.00000500 |
| logging slow query | 0.00000300 |
+——————————–+————+
15 rows in set (0.00 sec)
mysql> SHOW PROFILE FOR QUERY 28;
+————————————-+————+
| Status | Duration |
+————————————-+————+
| (initialization) | 0.00000350 |
| checking query cache for query | 0.00000750 |
| checking privileges on cached query | 0.00000500 |
| checking permissions | 0.00000525 |
| sending cached result to client | 0.00001275 |
| logging slow query | 0.00000450 |
+————————————-+————+
6 rows in set (0.00 sec)
mysql> SELECT sum( FORMAT(DURATION, 6)) AS DURATION FROM INFORMATION_SCHEMA.PROFILING WHERE QUERY_ID =27 ORDER BY SEQ;
+———-+
| DURATION |
+———-+
| 0.000326 |
+———-+
1 row in set (0.00 sec)
mysql> SELECT sum( FORMAT(DURATION, 6)) AS DURATION FROM INFORMATION_SCHEMA.PROFILING WHERE QUERY_ID =28 ORDER BY SEQ;
+———-+
| DURATION |
+———-+
| 0.000039 |
+———-+
1 row in set (0.00 sec)
mysql>
\u5f9e\u4e0a\u9762\u7684\u4f8b\u5b50\u4e2d\u6211\u5011\u53ef\u4ee5\u6e05\u6670\u7684\u770b\u51fa 2 \u6b21\u57f7\u884c count \u8a9e\u53e5\u7684\u5dee\u5225\uff0c SHOW PROFILE FOR QUERY 27 \u5c55\u73fe\u7684\u662f\u7b2c\u4e00\u6b21 count \u7d71\u8a08\u7684\u57f7\u884c\u904e\u7a0b\uff0c\u5305\u62ec\u4e86 Opening tables \u3001 Table lock \u7b49\u64cd\u4f5c \u3002\u800c SHOW PROFILE FOR QUERY 28 \u5c55\u793a\u4e86\u7b2c\u4e8c\u6b21 count \u7d71\u8a08\u7684\u57f7\u884c\u904e\u7a0b , \u7b2c\u4e8c\u6b21 count \u76f4\u63a5\u5f9e\u67e5\u8a62\u5feb\u53d6\u4e2d\u8fd4\u56de count \u7d71\u8a08\u7d50\u679c\uff0c\u901a\u904e\u5c0d\u7167 2 \u6b21\u7d71\u8a08\u7684\u7e3d\u57f7\u884c\u6642\u9593\u767c\u73fe\uff0c\u5feb\u53d6\u8b80\u7684\u901f\u5ea6\u63a5\u8fd1\u7269\u7406\u8b80\u7684 10 \u500d\u3002\u901a\u904e\u4f7f\u7528 SQL \u6548\u80fd\u5206\u6790\u5668\u53ef\u4ee5\u8aaa\u660e\u6211\u5011\u5c0d\u4e00\u4e9b\u6bd4\u8f03\u96e3\u4ee5\u78ba\u5b9a\u6548\u80fd\u554f\u984c\u7684 SQL \u9032\u884c\u8a3a\u65b7\uff0c\u627e\u51fa\u554f\u984c\u6839\u6e90\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
mysql \u7684 sql \u6548\u80fd\u5206\u6790\u5668\u4e3b\u8981\u7528\u9014\u662f\u986f\u793a sql \u57f7\u884c\u7684\u6574\u500b\u904e\u7a0b\u4e2d\u5404\u9805\u8cc7\u6e90\u7684\u4f7f\u7528\u60c5\u6cc1\u3002\u5206\u6790\u5668\u53ef\u4ee5\u66f4\u597d\u7684 […]<\/p>\n","protected":false},"author":1,"featured_media":507,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[20],"class_list":["post-15","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-linux","tag-linux"],"_links":{"self":[{"href":"https:\/\/por.tw\/linux\/wp-json\/wp\/v2\/posts\/15"}],"collection":[{"href":"https:\/\/por.tw\/linux\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/por.tw\/linux\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/por.tw\/linux\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/por.tw\/linux\/wp-json\/wp\/v2\/comments?post=15"}],"version-history":[{"count":0,"href":"https:\/\/por.tw\/linux\/wp-json\/wp\/v2\/posts\/15\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/por.tw\/linux\/wp-json\/wp\/v2\/media\/507"}],"wp:attachment":[{"href":"https:\/\/por.tw\/linux\/wp-json\/wp\/v2\/media?parent=15"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/por.tw\/linux\/wp-json\/wp\/v2\/categories?post=15"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/por.tw\/linux\/wp-json\/wp\/v2\/tags?post=15"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}