{"id":2290,"date":"2017-05-29T06:36:25","date_gmt":"2017-05-28T22:36:25","guid":{"rendered":"http:\/\/cn.hostease.com\/xueyuan\/?p=2290"},"modified":"2017-05-29T06:36:25","modified_gmt":"2017-05-28T22:36:25","slug":"mysql%e6%80%a7%e8%83%bd%e6%9f%a5%e7%9c%8b%ef%bc%88%e5%91%bd%e4%b8%ad%e7%8e%87%e6%85%a2%e6%9f%a5%e8%af%a2","status":"publish","type":"post","link":"https:\/\/cn.hostease.com\/xueyuan\/jishu\/shujuku\/mysql%e6%80%a7%e8%83%bd%e6%9f%a5%e7%9c%8b%ef%bc%88%e5%91%bd%e4%b8%ad%e7%8e%87%e6%85%a2%e6%9f%a5%e8%af%a2\/","title":{"rendered":"MYSQL\u6027\u80fd\u67e5\u770b\uff08\u547d\u4e2d\u7387,\u6162\u67e5\u8be2"},"content":{"rendered":"

\u7f51\u4e0a\u6709\u5f88\u591a\u7684\u6587\u7ae0\u6559\u600e\u4e48\u914d\u7f6eMySQL\u670d\u52a1\u5668\uff0c\u4f46\u8003\u8651\u5230\u670d\u52a1\u5668\u786c\u4ef6\u914d\u7f6e\u7684\u4e0d\u540c\uff0c\u5177\u4f53\u5e94\u7528\u7684\u5dee\u522b\uff0c\u90a3\u4e9b\u6587\u7ae0\u7684\u505a\u6cd5\u53ea\u80fd\u4f5c\u4e3a\u521d\u6b65\u8bbe\u7f6e\u53c2\u8003\uff0c\u6211\u4eec\u9700\u8981\u6839\u636e\u81ea\u5df1\u7684\u60c5\u51b5\u8fdb\u884c\u914d\u7f6e\u4f18\u5316\uff0c\u597d\u7684\u505a\u6cd5\u662fMySQL\u670d\u52a1\u5668\u7a33\u5b9a\u8fd0\u884c\u4e86\u4e00\u6bb5\u65f6\u95f4\u540e\u8fd0\u884c\uff0c\u6839\u636e\u670d\u52a1\u5668\u7684\u201d\u72b6\u6001\u201d\u8fdb\u884c\u4f18\u5316\u3002
\nmysql> show global status;
\n\u53ef\u4ee5\u5217\u51faMySQL\u670d\u52a1\u5668\u8fd0\u884c\u5404\u79cd\u72b6\u6001\u503c\uff0c\u53e6\u5916\uff0c\u67e5\u8be2MySQL\u670d\u52a1\u5668\u914d\u7f6e\u4fe1\u606f\u8bed\u53e5\uff1a
\nmysql> show variables;
\n\u4e00\u3001\u6162\u67e5\u8be2
\n<\/strong>\u3000\u3000mysql> show variables like ‘%slow%’;
\n+——————+——-+
\n| Variable_name | Value |
\n+——————+——-+
\n| log_slow_queries | ON |
\n| slow_launch_time | 2 |
\n+——————+——-+
\nmysql> show global status like ‘%slow%’;
\n+———————+——-+
\n| Variable_name | Value |
\n+———————+——-+
\n| Slow_launch_threads | 0 |
\n| Slow_queries | 4148 |
\n+———————+——-+<\/p>\n

\u914d\u7f6e\u4e2d\u6253\u5f00\u4e86\u8bb0\u5f55\u6162\u67e5\u8be2\uff0c\u6267\u884c\u65f6\u95f4\u8d85\u8fc72\u79d2\u7684\u5373\u4e3a\u6162\u67e5\u8be2\uff0c\u7cfb\u7edf\u663e\u793a\u67094148\u4e2a\u6162\u67e5\u8be2\uff0c\u4f60\u53ef\u4ee5\u5206\u6790\u6162\u67e5\u8be2\u65e5\u5fd7\uff0c\u627e\u51fa\u6709\u95ee\u9898\u7684SQL\u8bed\u53e5\uff0c\u6162\u67e5\u8be2\u65f6\u95f4\u4e0d\u5b9c\u8bbe\u7f6e\u8fc7\u957f\uff0c\u5426\u5219\u610f\u4e49\u4e0d\u5927\uff0c\u6700\u597d\u57285\u79d2\u4ee5\u5185\uff0c\u5982\u679c\u4f60\u9700\u8981\u5fae\u79d2\u7ea7\u522b\u7684\u6162\u67e5\u8be2\uff0c\u53ef\u4ee5\u8003\u8651\u7ed9MySQL\u6253\u8865\u4e01\uff1ahttps:\/\/www.percona.com\/docs\/wiki\/release:start<\/a>\uff0c\u8bb0\u5f97\u627e\u5bf9\u5e94\u7684\u7248\u672c\u3002
\n\u6253\u5f00\u6162\u67e5\u8be2\u65e5\u5fd7\u53ef\u80fd\u4f1a\u5bf9\u7cfb\u7edf\u6027\u80fd\u6709\u4e00\u70b9\u70b9\u5f71\u54cd\uff0c\u5982\u679c\u4f60\u7684MySQL\u662f\u4e3b-\u4ece\u7ed3\u6784\uff0c\u53ef\u4ee5\u8003\u8651\u6253\u5f00\u5176\u4e2d\u4e00\u53f0\u4ece\u670d\u52a1\u5668\u7684\u6162\u67e5\u8be2\u65e5\u5fd7\uff0c\u8fd9\u6837\u65e2\u53ef\u4ee5\u76d1\u63a7\u6162\u67e5\u8be2\uff0c\u5bf9\u7cfb\u7edf\u6027\u80fd\u5f71\u54cd\u53c8\u5c0f\u3002
\n\u4e8c\u3001\u8fde\u63a5\u6570<\/strong>
\n\u7ecf\u5e38\u4f1a\u9047\u89c1\u201dMySQL: ERROR 1040: Too many connections\u201d\u7684\u60c5\u51b5\uff0c\u4e00\u79cd\u662f\u8bbf\u95ee\u91cf\u786e\u5b9e\u5f88\u9ad8\uff0cMySQL\u670d\u52a1\u5668\u6297\u4e0d\u4f4f\uff0c\u8fd9\u4e2a\u65f6\u5019\u5c31\u8981\u8003\u8651\u589e\u52a0\u4ece\u670d\u52a1\u5668\u5206\u6563\u8bfb\u538b\u529b\uff0c\u53e6\u5916\u4e00\u79cd\u60c5\u51b5\u662fMySQL\u914d \u7f6e\u6587\u4ef6\u4e2dmax_connections\u503c\u8fc7\u5c0f\uff1a
\nmysql> show variables like ‘max_connections’;
\n+—————–+——-+
\n| Variable_name | Value |
\n+—————–+——-+
\n| max_connections | 256 |
\n+—————–+——-+<\/p>\n

\u8fd9\u53f0MySQL\u670d\u52a1\u5668\u6700\u5927\u8fde\u63a5\u6570\u662f256\uff0c\u7136\u540e\u67e5\u8be2\u4e00\u4e0b\u670d\u52a1\u5668\u54cd\u5e94\u7684\u6700\u5927\u8fde\u63a5\u6570\uff1a
\nmysql> show global status like \u2018Max_used_connections\u2019;
\nMySQL\u670d\u52a1\u5668\u8fc7\u53bb\u7684\u6700\u5927\u8fde\u63a5\u6570\u662f245\uff0c\u6ca1\u6709\u8fbe\u5230\u670d\u52a1\u5668\u8fde\u63a5\u6570\u4e0a\u9650256\uff0c\u5e94\u8be5\u6ca1\u6709\u51fa\u73b01040\u9519\u8bef\uff0c\u6bd4\u8f83\u7406\u60f3\u7684\u8bbe\u7f6e\u662f\uff1a
\nMax_used_connections \/ max_connections * 100% \u2248 85%
\n\u6700\u5927\u8fde\u63a5\u6570\u5360\u4e0a\u9650\u8fde\u63a5\u6570\u768485%\u5de6\u53f3\uff0c\u5982\u679c\u53d1\u73b0\u6bd4\u4f8b\u572810%\u4ee5\u4e0b\uff0cMySQL\u670d\u52a1\u5668\u8fde\u63a5\u6570\u4e0a\u9650\u8bbe\u7f6e\u7684\u8fc7\u9ad8\u4e86\u3002
\n\u4e09\u3001Key_buffer_size
\n<\/strong>\u3000\u3000key_buffer_size\u662f\u5bf9MyISAM\u8868\u6027\u80fd\u5f71\u54cd\u6700\u5927\u7684\u4e00\u4e2a\u53c2\u6570\uff0c\u4e0b\u9762\u4e00\u53f0\u4ee5MyISAM\u4e3a\u4e3b\u8981\u5b58\u50a8\u5f15\u64ce\u670d\u52a1\u5668\u7684\u914d\u7f6e\uff1a
\nmysql> show variables like \u2018key_buffer_size\u2019;
\n+—————–+————+
\n| Variable_name | Value |
\n+—————–+————+
\n| key_buffer_size | 536870912 |
\n+—————–+————+<\/p>\n

\u5206\u914d\u4e86512MB\u5185\u5b58\u7ed9key_buffer_size\uff0c\u6211\u4eec\u518d\u770b\u4e00\u4e0bkey_buffer_size\u7684\u4f7f\u7528\u60c5\u51b5\uff1a
\nmysql> show global status like ‘key_read%’;
\n+————————+————-+
\n| Variable_name | Value | mysql
\n+————————+————-+
\n| Key_read_requests | 27813678764 |
\n| Key_reads | 6798830 |
\n+————————+————-+<\/p>\n

\u4e00\u5171\u670927813678764\u4e2a\u7d22\u5f15\u8bfb\u53d6\u8bf7\u6c42\uff0c\u67096798830\u4e2a\u8bf7\u6c42\u5728\u5185\u5b58\u4e2d\u6ca1\u6709\u627e\u5230\u76f4\u63a5\u4ece\u786c\u76d8\u8bfb\u53d6\u7d22\u5f15\uff0c\u8ba1\u7b97\u7d22\u5f15\u672a\u547d\u4e2d\u7f13\u5b58\u7684\u6982\u7387\uff1a
\nkey_cache_miss_rate = Key_reads \/ Key_read_requests * 100%
\n\u6bd4\u5982\u4e0a\u9762\u7684\u6570\u636e\uff0ckey_cache_miss_rate\u4e3a0.0244%\uff0c4000\u4e2a\u7d22\u5f15\u8bfb\u53d6\u8bf7\u6c42\u624d\u6709\u4e00\u4e2a\u76f4\u63a5\u8bfb\u786c\u76d8\uff0c\u5df2\u7ecf\u5f88BT \u4e86,key_cache_miss_rate\u57280.1%\u4ee5\u4e0b\u90fd\u5f88\u597d(\u6bcf1000\u4e2a\u8bf7\u6c42\u6709\u4e00\u4e2a\u76f4\u63a5\u8bfb\u786c\u76d8)\uff0c\u5982\u679ckey_cache_miss_rate\u5728 0.01%\u4ee5\u4e0b\u7684\u8bdd\uff0ckey_buffer_size\u5206\u914d\u7684\u8fc7\u591a\uff0c\u53ef\u4ee5\u9002\u5f53\u51cf\u5c11\u3002
\nMySQL\u670d\u52a1\u5668\u8fd8\u63d0\u4f9b\u4e86key_blocks_*\u53c2\u6570\uff1a
\nmysql> show global status like ‘key_blocks_u%’;
\n+————————+————-+
\n| Variable_name | Value |
\n+————————+————-+
\n| Key_blocks_unused | 0 |
\n| Key_blocks_used | 413543 |
\n+————————+————-+<\/p>\n

Key_blocks_unused\u8868\u793a\u672a\u4f7f\u7528\u7684\u7f13\u5b58\u7c07(blocks)\u6570\uff0cKey_blocks_used\u8868\u793a\u66fe\u7ecf\u7528\u5230\u7684\u6700\u5927\u7684blocks\u6570\uff0c\u6bd4\u5982\u8fd9 \u53f0\u670d\u52a1\u5668\uff0c\u6240\u6709\u7684\u7f13\u5b58\u90fd\u7528\u5230\u4e86\uff0c\u8981\u4e48\u589e\u52a0key_buffer_size\uff0c\u8981\u4e48\u5c31\u662f\u8fc7\u6e21\u7d22\u5f15\u4e86\uff0c\u628a\u7f13\u5b58\u5360\u6ee1\u4e86\u3002\u6bd4\u8f83\u7406\u60f3\u7684\u8bbe\u7f6e\uff1a
\nKey_blocks_used \/ (Key_blocks_unused + Key_blocks_used) * 100% \u2248 80%
\n\u56db\u3001\u4e34\u65f6\u8868
\n<\/strong>\u3000\u3000mysql> show global status like ‘created_tmp%’;
\n+————————-+———+
\n| Variable_name | Value |
\n+————————-+———+
\n| Created_tmp_disk_tables | 21197 |
\n| Created_tmp_files | 58 |
\n| Created_tmp_tables | 1771587 |
\n+————————-+———+<\/p>\n

\u6bcf\u6b21\u521b\u5efa\u4e34\u65f6\u8868\uff0cCreated_tmp_tables\u589e\u52a0\uff0c\u5982\u679c\u662f\u5728\u78c1\u76d8\u4e0a\u521b\u5efa\u4e34\u65f6\u8868\uff0cCreated_tmp_disk_tables\u4e5f\u589e\u52a0,Created_tmp_files\u8868\u793aMySQL\u670d\u52a1\u521b\u5efa\u7684\u4e34\u65f6\u6587\u4ef6\u6587\u4ef6\u6570\uff0c\u6bd4\u8f83\u7406\u60f3\u7684\u914d\u7f6e\u662f\uff1a
\nCreated_tmp_disk_tables \/ Created_tmp_tables * 100% <= 25%
\n\u6bd4\u5982\u4e0a\u9762\u7684\u670d\u52a1\u5668Created_tmp_disk_tables \/ Created_tmp_tables * 100% = 1.20%\uff0c\u5e94\u8be5\u76f8\u5f53\u597d\u4e86\u3002\u6211\u4eec\u518d\u770b\u4e00\u4e0bMySQL\u670d\u52a1\u5668\u5bf9\u4e34\u65f6\u8868\u7684\u914d\u7f6e\uff1a
\nmysql> show variables where Variable_name in (‘tmp_table_size’, ‘max_heap_table_size’);
\n+———————+———–+
\n| Variable_name | Value |
\n+———————+———–+
\n| max_heap_table_size | 268435456 |
\n| tmp_table_size | 536870912 |
\n+———————+———–+<\/p>\n

\u53ea\u6709256MB\u4ee5\u4e0b\u7684\u4e34\u65f6\u8868\u624d\u80fd\u5168\u90e8\u653e\u5185\u5b58\uff0c\u8d85\u8fc7\u7684\u5c31\u4f1a\u7528\u5230\u786c\u76d8\u4e34\u65f6\u8868\u3002
\n\u4e94\u3001Open Table\u60c5\u51b5<\/strong>
\nmysql> show global status like ‘open%tables%’;
\n+—————+——-+
\n| Variable_name | Value |
\n+—————+——-+
\n| Open_tables | 919 |
\n| Opened_tables | 1951 |
\n+—————+——-+<\/p>\n

Open_tables\u8868\u793a\u6253\u5f00\u8868\u7684\u6570\u91cf\uff0cOpened_tables\u8868\u793a\u6253\u5f00\u8fc7\u7684\u8868\u6570\u91cf\uff0c\u5982\u679cOpened_tables\u6570\u91cf\u8fc7\u5927\uff0c\u8bf4\u660e\u914d\u7f6e\u4e2d table_cache(5.1.3\u4e4b\u540e\u8fd9\u4e2a\u503c\u53eb\u505atable_open_cache)\u503c\u53ef\u80fd\u592a\u5c0f\uff0c\u6211\u4eec\u67e5\u8be2\u4e00\u4e0b\u670d\u52a1\u5668table_cache\u503c\uff1a
\nmysql> show variables like ‘table_cache’;
\n+—————+——-+
\n| Variable_name | Value |
\n+—————+——-+
\n| table_cache | 2048 |
\n+—————+——-+
\n\u6bd4\u8f83\u5408\u9002\u7684\u503c\u4e3a\uff1a
\nOpen_tables \/ Opened_tables * 100% >= 85%
\nOpen_tables \/ table_cache * 100% <= 95%
\n\u3000\u516d\u3001\u8fdb\u7a0b\u4f7f\u7528\u60c5\u51b5
\n<\/strong>\u3000\u3000mysql> show global status like \u2018Thread%\u2019;
\n+——————-+——-+
\n| Variable_name | Value |
\n+——————-+——-+
\n| Threads_cached | 46 |
\n| Threads_connected | 2 |
\n| Threads_created | 570 |
\n| Threads_running | 1 |
\n+——————-+——-+<\/p>\n

\u5982\u679c\u6211\u4eec\u5728MySQL\u670d\u52a1\u5668\u914d\u7f6e\u6587\u4ef6\u4e2d\u8bbe\u7f6e\u4e86thread_cache_size\uff0c\u5f53\u5ba2\u6237\u7aef\u65ad\u5f00\u4e4b\u540e\uff0c\u670d\u52a1\u5668\u5904\u7406\u6b64\u5ba2\u6237\u7684\u7ebf\u7a0b\u5c06\u4f1a\u7f13\u5b58\u8d77\u6765\u4ee5\u54cd\u5e94\u4e0b\u4e00\u4e2a\u5ba2 \u6237\u800c\u4e0d\u662f\u9500\u6bc1(\u524d\u63d0\u662f\u7f13\u5b58\u6570\u672a\u8fbe\u4e0a\u9650)\u3002Threads_created\u8868\u793a\u521b\u5efa\u8fc7\u7684\u7ebf\u7a0b\u6570\uff0c\u5982\u679c\u53d1\u73b0Threads_created\u503c\u8fc7\u5927\u7684\u8bdd\uff0c\u8868\u660e MySQL\u670d\u52a1\u5668\u4e00\u76f4\u5728\u521b\u5efa\u7ebf\u7a0b\uff0c\u8fd9\u4e5f\u662f\u6bd4\u8f83\u8017\u8d44\u6e90\uff0c\u53ef\u4ee5\u9002\u5f53\u589e\u52a0\u914d\u7f6e\u6587\u4ef6\u4e2dthread_cache_size\u503c\uff0c\u67e5\u8be2\u670d\u52a1\u5668 thread_cache_size\u914d\u7f6e\uff1a
\nmysql> show variables like ‘thread_cache_size’;
\n+——————-+——-+
\n| Variable_name | Value |
\n+——————-+——-+
\n| thread_cache_size | 64 |
\n+——————-+——-+<\/p>\n

\u793a\u4f8b\u4e2d\u7684\u670d\u52a1\u5668\u8fd8\u662f\u633a\u5065\u5eb7\u7684\u3002
\n\u4e03\u3001\u67e5\u8be2\u7f13\u5b58(query cache)
\n<\/strong>\u3000\u3000mysql> show global status like ‘qcache%’;
\n+————————-+———–+
\n| Variable_name | Value |
\n+————————-+———–+
\n| Qcache_free_blocks | 22756 |
\n| Qcache_free_memory | 76764704 |
\n| Qcache_hits | 213028692 |
\n| Qcache_inserts | 208894227 |
\n| Qcache_lowmem_prunes | 4010916 |
\n| Qcache_not_cached | 13385031 |
\n| Qcache_queries_in_cache | 43560 |
\n| Qcache_total_blocks | 111212 |
\n+————————-+———–+<\/p>\n

MySQL\u67e5\u8be2\u7f13\u5b58\u53d8\u91cf\u89e3\u91ca\uff1a
\nQcache_free_blocks\uff1a\u7f13\u5b58\u4e2d\u76f8\u90bb\u5185\u5b58\u5757\u7684\u4e2a\u6570\u3002\u6570\u76ee\u5927\u8bf4\u660e\u53ef\u80fd\u6709\u788e\u7247\u3002FLUSH QUERY CACHE\u4f1a\u5bf9\u7f13\u5b58\u4e2d\u7684\u788e\u7247\u8fdb\u884c\u6574\u7406\uff0c\u4ece\u800c\u5f97\u5230\u4e00\u4e2a\u7a7a\u95f2\u5757\u3002
\nQcache_free_memory\uff1a\u7f13\u5b58\u4e2d\u7684\u7a7a\u95f2\u5185\u5b58\u3002
\nQcache_hits\uff1a\u6bcf\u6b21\u67e5\u8be2\u5728\u7f13\u5b58\u4e2d\u547d\u4e2d\u65f6\u5c31\u589e\u5927
\nQcache_inserts\uff1a\u6bcf\u6b21\u63d2\u5165\u4e00\u4e2a\u67e5\u8be2\u65f6\u5c31\u589e\u5927\u3002\u547d\u4e2d\u6b21\u6570\u9664\u4ee5\u63d2\u5165\u6b21\u6570\u5c31\u662f\u4e0d\u4e2d\u6bd4\u7387\u3002
\nQcache_lowmem_prunes\uff1a\u7f13\u5b58\u51fa\u73b0\u5185\u5b58\u4e0d\u8db3\u5e76\u4e14\u5fc5\u987b\u8981\u8fdb\u884c\u6e05\u7406\u4ee5\u4fbf\u4e3a\u66f4\u591a\u67e5\u8be2\u63d0\u4f9b\u7a7a\u95f4\u7684\u6b21\u6570\u3002\u8fd9\u4e2a\u6570\u5b57\u6700\u597d\u957f\u65f6\u95f4\u6765\u770b;\u5982\u679c\u8fd9\u4e2a\u6570 \u5b57\u5728\u4e0d\u65ad\u589e\u957f\uff0c\u5c31\u8868\u793a\u53ef\u80fd\u788e\u7247\u975e\u5e38\u4e25\u91cd\uff0c\u6216\u8005\u5185\u5b58\u5f88\u5c11\u3002(\u4e0a\u9762\u7684 free_blocks\u548cfree_memory\u53ef\u4ee5\u544a\u8bc9\u60a8\u5c5e\u4e8e\u54ea\u79cd\u60c5\u51b5)
\nQcache_not_cached\uff1a\u4e0d\u9002\u5408\u8fdb\u884c\u7f13\u5b58\u7684\u67e5\u8be2\u7684\u6570\u91cf\uff0c\u901a\u5e38\u662f\u7531\u4e8e\u8fd9\u4e9b\u67e5\u8be2\u4e0d\u662f SELECT \u8bed\u53e5\u6216\u8005\u7528\u4e86now()\u4e4b\u7c7b\u7684\u51fd\u6570\u3002
\nQcache_queries_in_cache\uff1a\u5f53\u524d\u7f13\u5b58\u7684\u67e5\u8be2(\u548c\u54cd\u5e94)\u7684\u6570\u91cf\u3002
\nQcache_total_blocks\uff1a\u7f13\u5b58\u4e2d\u5757\u7684\u6570\u91cf\u3002
\n\u6211\u4eec\u518d\u67e5\u8be2\u4e00\u4e0b\u670d\u52a1\u5668\u5173\u4e8equery_cache\u7684\u914d\u7f6e\uff1a
\nmysql> show variables like ‘query_cache%’;
\n+——————————+———–+
\n| Variable_name | Value |
\n+——————————+———–+
\n| query_cache_limit | 2097152 |
\n| query_cache_min_res_unit | 4096 |
\n| query_cache_size | 203423744 |
\n| query_cache_type | ON |
\n| query_cache_wlock_invalidate | OFF |<\/p>\n

+\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014+\u2014\u2014\u2014\u2013+
\n\u5404\u5b57\u6bb5\u7684\u89e3\u91ca\uff1a
\nquery_cache_limit\uff1a\u8d85\u8fc7\u6b64\u5927\u5c0f\u7684\u67e5\u8be2\u5c06\u4e0d\u7f13\u5b58
\nquery_cache_min_res_unit\uff1a\u7f13\u5b58\u5757\u7684\u6700\u5c0f\u5927\u5c0f
\nquery_cache_size\uff1a\u67e5\u8be2\u7f13\u5b58\u5927\u5c0f
\nquery_cache_type\uff1a\u7f13\u5b58\u7c7b\u578b\uff0c\u51b3\u5b9a\u7f13\u5b58\u4ec0\u4e48\u6837\u7684\u67e5\u8be2\uff0c\u793a\u4f8b\u4e2d\u8868\u793a\u4e0d\u7f13\u5b58 select sql_no_cache \u67e5\u8be2
\nquery_cache_wlock_invalidate\uff1a\u5f53\u6709\u5176\u4ed6\u5ba2\u6237\u7aef\u6b63\u5728\u5bf9MyISAM\u8868\u8fdb\u884c\u5199\u64cd\u4f5c\u65f6\uff0c\u5982\u679c\u67e5\u8be2\u5728query cache\u4e2d\uff0c\u662f\u5426\u8fd4\u56decache\u7ed3\u679c\u8fd8\u662f\u7b49\u5199\u64cd\u4f5c\u5b8c\u6210\u518d\u8bfb\u8868\u83b7\u53d6\u7ed3\u679c\u3002
\nquery_cache_min_res_unit\u7684\u914d\u7f6e\u662f\u4e00\u67c4\u201d\u53cc\u5203\u5251\u201d\uff0c\u9ed8\u8ba4\u662f4KB\uff0c\u8bbe\u7f6e\u503c\u5927\u5bf9\u5927\u6570\u636e\u67e5\u8be2\u6709\u597d\u5904\uff0c\u4f46\u5982\u679c\u4f60\u7684\u67e5\u8be2\u90fd\u662f\u5c0f\u6570\u636e\u67e5\u8be2\uff0c\u5c31\u5bb9\u6613\u9020\u6210\u5185\u5b58\u788e\u7247\u548c\u6d6a\u8d39\u3002
\n\u67e5\u8be2\u7f13\u5b58\u788e\u7247\u7387 = Qcache_free_blocks \/ Qcache_total_blocks * 100%
\n\u5982\u679c\u67e5\u8be2\u7f13\u5b58\u788e\u7247\u7387\u8d85\u8fc720%\uff0c\u53ef\u4ee5\u7528FLUSH QUERY CACHE\u6574\u7406\u7f13\u5b58\u788e\u7247\uff0c\u6216\u8005\u8bd5\u8bd5\u51cf\u5c0fquery_cache_min_res_unit\uff0c\u5982\u679c\u4f60\u7684\u67e5\u8be2\u90fd\u662f\u5c0f\u6570\u636e\u91cf\u7684\u8bdd\u3002
\n\u67e5\u8be2\u7f13\u5b58\u5229\u7528\u7387 = (query_cache_size – Qcache_free_memory) \/ query_cache_size * 100%
\n\u67e5\u8be2\u7f13\u5b58\u5229\u7528\u7387\u572825%\u4ee5\u4e0b\u7684\u8bdd\u8bf4\u660equery_cache_size\u8bbe\u7f6e\u7684\u8fc7\u5927\uff0c\u53ef\u9002\u5f53\u51cf\u5c0f;\u67e5\u8be2\u7f13\u5b58\u5229\u7528\u7387\u572880%\u4ee5\u4e0a\u800c\u4e14Qcache_lowmem_prunes > 50\u7684\u8bdd\u8bf4\u660equery_cache_size\u53ef\u80fd\u6709\u70b9\u5c0f\uff0c\u8981\u4e0d\u5c31\u662f\u788e\u7247\u592a\u591a\u3002
\n\u67e5\u8be2\u7f13\u5b58\u547d\u4e2d\u7387 = (Qcache_hits – Qcache_inserts) \/ Qcache_hits * 100%
\n\u793a\u4f8b\u670d\u52a1\u5668 \u67e5\u8be2\u7f13\u5b58\u788e\u7247\u7387 = 20.46%\uff0c\u67e5\u8be2\u7f13\u5b58\u5229\u7528\u7387 = 62.26%\uff0c\u67e5\u8be2\u7f13\u5b58\u547d\u4e2d\u7387 = 1.94%\uff0c\u547d\u4e2d\u7387\u5f88\u5dee\uff0c\u53ef\u80fd\u5199\u64cd\u4f5c\u6bd4\u8f83\u9891\u7e41\u5427\uff0c\u800c\u4e14\u53ef\u80fd\u6709\u4e9b\u788e\u7247\u3002
\n\u516b\u3001\u6392\u5e8f\u4f7f\u7528\u60c5\u51b5
\n<\/strong>\u3000\u3000mysql> show global status like ‘sort%’;
\n+——————-+————+
\n| Variable_name | Value |
\n+——————-+————+
\n| Sort_merge_passes | 29 |
\n| Sort_range | 37432840 |
\n| Sort_rows | 9178691532 |
\n| Sort_scan | 1860569 |
\n+——————-+————+<\/p>\n

Sort_merge_passes \u5305\u62ec\u4e24\u6b65\u3002MySQL \u9996\u5148\u4f1a\u5c1d\u8bd5\u5728\u5185\u5b58\u4e2d\u505a\u6392\u5e8f\uff0c\u4f7f\u7528\u7684\u5185\u5b58\u5927\u5c0f\u7531\u7cfb\u7edf\u53d8\u91cf Sort_buffer_size \u51b3\u5b9a\uff0c\u5982\u679c\u5b83\u7684\u5927\u5c0f\u4e0d\u591f\u628a\u6240\u6709\u7684\u8bb0\u5f55\u90fd\u8bfb\u5230\u5185\u5b58\u4e2d\uff0cMySQL \u5c31\u4f1a\u628a\u6bcf\u6b21\u5728\u5185\u5b58\u4e2d\u6392\u5e8f\u7684\u7ed3\u679c\u5b58\u5230\u4e34\u65f6\u6587\u4ef6\u4e2d\uff0c\u7b49 MySQL \u627e\u5230\u6240\u6709\u8bb0\u5f55\u4e4b\u540e\uff0c\u518d\u628a\u4e34\u65f6\u6587\u4ef6\u4e2d\u7684\u8bb0\u5f55\u505a\u4e00\u6b21\u6392\u5e8f\u3002\u8fd9\u518d\u6b21\u6392\u5e8f\u5c31\u4f1a\u589e\u52a0 Sort_merge_passes\u3002\u5b9e\u9645\u4e0a\uff0cMySQL \u4f1a\u7528\u53e6\u4e00\u4e2a\u4e34\u65f6\u6587\u4ef6\u6765\u5b58\u518d\u6b21\u6392\u5e8f\u7684\u7ed3\u679c\uff0c\u6240\u4ee5\u901a\u5e38\u4f1a\u770b\u5230 Sort_merge_passes \u589e\u52a0\u7684\u6570\u503c\u662f\u5efa\u4e34\u65f6\u6587\u4ef6\u6570\u7684\u4e24\u500d\u3002\u56e0\u4e3a\u7528\u5230\u4e86\u4e34\u65f6\u6587\u4ef6\uff0c\u6240\u4ee5\u901f\u5ea6\u53ef\u80fd\u4f1a\u6bd4\u8f83\u6162\uff0c\u589e\u52a0 Sort_buffer_size \u4f1a\u51cf\u5c11 Sort_merge_passes \u548c \u521b\u5efa\u4e34\u65f6\u6587\u4ef6\u7684\u6b21\u6570\u3002\u4f46\u76f2\u76ee\u7684\u589e\u52a0 Sort_buffer_size \u5e76\u4e0d\u4e00\u5b9a\u80fd\u63d0\u9ad8\u901f\u5ea6\uff0c
\n\u53e6\u5916\uff0c\u589e\u52a0read_rnd_buffer_size(3.2.3\u662frecord_rnd_buffer_size)\u7684\u503c\u5bf9\u6392\u5e8f\u7684\u64cd\u4f5c\u4e5f\u6709\u4e00\u70b9\u7684\u597d\u5904\uff0c
\n\u4e5d\u3001\u6587\u4ef6\u6253\u5f00\u6570(open_files)
\n<\/strong>\u3000\u3000mysql> show global status like ‘open_files’;
\n+—————+——-+
\n| Variable_name | Value |
\n+—————+——-+
\n| Open_files | 1410 |
\n+—————+——-+
\nmysql> show variables like ‘open_files_limit’;
\n+——————+——-+
\n| Variable_name | Value |
\n+——————+——-+
\n| open_files_limit | 4590 |
\n+——————+——-+<\/p>\n

\u6bd4\u8f83\u5408\u9002\u7684\u8bbe\u7f6e\uff1aOpen_files \/ open_files_limit * 100% <= 75%
\n\u5341\u3001\u8868\u9501\u60c5\u51b5
\n<\/strong>\u3000\u3000mysql> show global status like ‘table_locks%’;
\n+———————–+———–+
\n| Variable_name | Value |
\n+———————–+———–+
\n| Table_locks_immediate | 490206328 |
\n| Table_locks_waited | 2084912 |
\n+———————–+———–+<\/p>\n

Table_locks_immediate\u8868\u793a\u7acb\u5373\u91ca\u653e\u8868\u9501\u6570\uff0cTable_locks_waited\u8868\u793a\u9700\u8981\u7b49\u5f85\u7684\u8868\u9501\u6570\uff0c\u5982\u679c Table_locks_immediate \/ Table_locks_waited > 5000\uff0c\u6700\u597d\u91c7\u7528InnoDB\u5f15\u64ce\uff0c\u56e0\u4e3aInnoDB\u662f\u884c\u9501\u800cMyISAM\u662f\u8868\u9501\uff0c\u5bf9\u4e8e\u9ad8\u5e76\u53d1\u5199\u5165\u7684\u5e94\u7528InnoDB\u6548\u679c\u4f1a\u597d\u4e9b\u3002\u793a\u4f8b\u4e2d\u7684\u670d\u52a1\u5668 Table_locks_immediate \/ Table_locks_waited = 235\uff0cMyISAM\u5c31\u8db3\u591f\u4e86\u3002
\n\u5341\u4e00\u3001\u8868\u626b\u63cf\u60c5\u51b5
\n<\/strong>\u3000\u3000mysql> show global status like ‘handler_read%’;
\n+———————–+————-+
\n| Variable_name | Value |
\n+———————–+————-+
\n| Handler_read_first | 5803750 |
\n| Handler_read_key | 6049319850 |
\n| Handler_read_next | 94440908210 |
\n| Handler_read_prev | 34822001724 |
\n| Handler_read_rnd | 405482605 |
\n| Handler_read_rnd_next | 18912877839 |
\n+———————–+————-+
\nmysql> show global status like ‘com_select’;
\n+—————+———–+
\n| Variable_name | Value |
\n+—————+———–+
\n| Com_select | 222693559 |
\n+—————+———–+<\/p>\n

\u8ba1\u7b97\u8868\u626b\u63cf\u7387\uff1a
\n\u8868\u626b\u63cf\u7387 = Handler_read_rnd_next \/ Com_select
\n\u5982\u679c\u8868\u626b\u63cf\u7387\u8d85\u8fc74000\uff0c\u8bf4\u660e\u8fdb\u884c\u4e86\u592a\u591a\u8868\u626b\u63cf\uff0c\u5f88\u6709\u53ef\u80fd\u7d22\u5f15\u6ca1\u6709\u5efa\u597d\uff0c\u589e\u52a0read_buffer_size\u503c\u4f1a\u6709\u4e00\u4e9b\u597d\u5904\uff0c\u4f46\u6700\u597d\u4e0d\u8981\u8d85\u8fc78MB\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"

\u7f51\u4e0a\u6709\u5f88\u591a\u7684\u6587\u7ae0\u6559\u600e\u4e48\u914d\u7f6eMySQL\u670d\u52a1\u5668\uff0c\u4f46\u8003\u8651\u5230\u670d\u52a1\u5668\u786c\u4ef6\u914d\u7f6e\u7684\u4e0d\u540c\uff0c\u5177\u4f53\u5e94\u7528\u7684\u5dee\u522b\uff0c\u90a3\u4e9b\u6587\u7ae0\u7684\u505a\u6cd5\u53ea\u80fd\u4f5c … \u9605\u8bfb\u66f4\u591a<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[10],"tags":[45],"class_list":["post-2290","post","type-post","status-publish","format-standard","hentry","category-shujuku","tag-mysql"],"aioseo_notices":[],"jetpack_featured_media_url":"","jetpack-related-posts":[],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/posts\/2290","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/comments?post=2290"}],"version-history":[{"count":1,"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/posts\/2290\/revisions"}],"predecessor-version":[{"id":2291,"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/posts\/2290\/revisions\/2291"}],"wp:attachment":[{"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/media?parent=2290"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/categories?post=2290"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/tags?post=2290"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}