{"id":5445,"date":"2024-11-14T11:04:15","date_gmt":"2024-11-14T03:04:15","guid":{"rendered":"https:\/\/fwq.ai\/blog\/5445\/"},"modified":"2024-11-14T11:04:15","modified_gmt":"2024-11-14T03:04:15","slug":"mysql%e8%af%ad%e6%b3%95%e6%8f%90%e7%a4%ba%e6%80%8e%e4%b9%88%e6%9f%a5%e7%9c%8b","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/5445\/","title":{"rendered":"mysql\u8bed\u6cd5\u63d0\u793a\u600e\u4e48\u67e5\u770b"},"content":{"rendered":"

\n \u5728 mysql \u4e2d\u67e5\u770b\u8bed\u6cd5\u63d0\u793a\u7684\u65b9\u6cd5\uff1a\u4f7f\u7528 explain \u547d\u4ee4\u67e5\u770b\u67e5\u8be2\u6267\u884c\u8ba1\u5212\uff0c\u5176\u4e2d\u5305\u62ec\u8bed\u6cd5\u63d0\u793a\u3002\u5728 explain \u8f93\u51fa\u7684 extra \u5217\u4e2d\u67e5\u627e\u8bed\u6cd5\u63d0\u793a\uff0c\u5b83\u4ee5\u7279\u5b9a\u7684\u63aa\u8f9e\u51fa\u73b0\uff0c\u4f8b\u5982 “using index” \u6216 “using where”\u3002\u7406\u89e3\u8bed\u6cd5\u63d0\u793a\uff0c\u5b83\u53ef\u4ee5\u5e2e\u52a9\u60a8\u4e86\u89e3\u67e5\u8be2\u6267\u884c\u7684\u65b9\u5f0f\u5e76\u4f18\u5316\u6027\u80fd\u3002\u4f8b\u5982\uff0c\u51fa\u73b0 “using filesort” \u8868\u660e\u9700\u8981\u6dfb\u52a0\u7d22\u5f15\u6216\u91cd\u5199\u67e5\u8be2\u4ee5\u907f\u514d\u6392\u5e8f\u3002\n<\/p><\/blockquote>\n

\"mysql\u8bed\u6cd5\u63d0\u793a\u600e\u4e48\u67e5\u770b\u63d2\u56fe\"<\/p>\n

\u5982\u4f55\u5728 MySQL \u4e2d\u67e5\u770b\u8bed\u6cd5\u63d0\u793a<\/strong><\/p>\n

\u5728 MySQL \u4e2d\u67e5\u770b\u8bed\u6cd5\u63d0\u793a\u662f\u4f18\u5316\u67e5\u8be2\u6027\u80fd\u548c\u907f\u514d\u8bed\u6cd5\u9519\u8bef\u7684\u91cd\u8981\u4e00\u6b65\u3002\u4ee5\u4e0b\u65b9\u6cd5\u53ef\u5e2e\u52a9\u60a8\u67e5\u770b\u8bed\u6cd5\u63d0\u793a\uff1a<\/p>\n

\u4f7f\u7528 EXPLAIN \u547d\u4ee4<\/strong><\/p>\n

EXPLAIN \u547d\u4ee4\u663e\u793a\u6709\u5173\u67e5\u8be2\u6267\u884c\u8ba1\u5212\u7684\u4fe1\u606f\uff0c\u5176\u4e2d\u5305\u62ec\u8bed\u6cd5\u63d0\u793a\u3002\u8981\u4f7f\u7528\u5b83\uff0c\u8bf7\u5728\u67e5\u8be2\u524d\u6dfb\u52a0 EXPLAIN \u5173\u952e\u5b57\u3002\u4f8b\u5982\uff1a<\/p>\n

EXPLAIN SELECT * FROM table_name WHERE id = 1;<\/pre>\n
 \u767b\u5f55\u540e\u590d\u5236 <\/p>\n
\u8f93\u51fa\u89e3\u91ca<\/strong><\/p>\n
EXPLAIN \u8f93\u51fa\u662f\u4e00\u4e2a\u8868\u683c\uff0c\u5305\u542b\u4ee5\u4e0b\u4fe1\u606f\uff1a<\/p>\n
    \n
  •  id\uff1a<\/strong> \u5b50\u67e5\u8be2\u7684 ID<\/li>\n
  •  select_type\uff1a<\/strong> \u67e5\u8be2\u7c7b\u578b\uff08\u4f8b\u5982\uff0cSIMPLE\u3001PRIMARY\uff09<\/li>\n
  •  table\uff1a<\/strong> \u8bbf\u95ee\u7684\u8868<\/li>\n
  •  type\uff1a<\/strong> \u7528\u4e8e\u8868\u4e2d\u7684\u7d22\u5f15\u7c7b\u578b\uff08\u4f8b\u5982\uff0cALL\u3001RANGE\uff09<\/li>\n
  •  possible_keys\uff1a<\/strong> \u53ef\u7528\u4e8e\u8868\u7684\u7d22\u5f15<\/li>\n
  •  key\uff1a<\/strong> \u5b9e\u9645\u4f7f\u7528\u7684\u7d22\u5f15<\/li>\n
  •  rows\uff1a<\/strong> \u4f30\u8ba1\u626b\u63cf\u7684\u884c\u6570<\/li>\n
  •  Extra\uff1a<\/strong> \u5176\u4ed6\u4fe1\u606f\uff0c\u5305\u62ec\u8bed\u6cd5\u63d0\u793a<\/li>\n<\/ul>\n
    \u67e5\u770b\u8bed\u6cd5\u63d0\u793a<\/strong><\/p>\n
    \u5728 EXPLAIN \u8f93\u51fa\u7684 Extra \u5217\u4e2d\u67e5\u627e\u8bed\u6cd5\u63d0\u793a\u3002\u5b83\u901a\u5e38\u4ee5\u4ee5\u4e0b\u5f62\u5f0f\u51fa\u73b0\uff1a<\/p>\n
      \n
    •  Using index<\/strong>\uff1a\u67e5\u8be2\u4f7f\u7528\u4e86\u7d22\u5f15\u3002<\/li>\n
    •  Using where<\/strong>\uff1a\u67e5\u8be2\u4f7f\u7528\u4e86 WHERE \u5b50\u53e5\u3002<\/li>\n
    •  Using temporary<\/strong>\uff1a\u67e5\u8be2\u4f7f\u7528\u4e86\u4e34\u65f6\u8868\u3002<\/li>\n
    •  Using filesort<\/strong>\uff1a\u67e5\u8be2\u4f7f\u7528\u4e86\u6587\u4ef6\u6392\u5e8f\u3002<\/li>\n<\/ul>\n
      \u7406\u89e3\u8bed\u6cd5\u63d0\u793a<\/strong><\/p>\n
      \u8bed\u6cd5\u63d0\u793a\u53ef\u4ee5\u5e2e\u52a9\u60a8\u4e86\u89e3\u67e5\u8be2\u6267\u884c\u7684\u65b9\u5f0f\u4ee5\u53ca\u53ef\u4ee5\u91c7\u53d6\u54ea\u4e9b\u63aa\u65bd\u6765\u63d0\u9ad8\u6027\u80fd\u3002\u4f8b\u5982\uff1a<\/p>\n
        \n
      •  \u5982\u679c\u51fa\u73b0 Using filesort<\/strong>\uff0c\u5219\u8868\u660e\u67e5\u8be2\u6b63\u5728\u5bf9\u6570\u636e\u8fdb\u884c\u6392\u5e8f\uff0c\u8fd9\u53ef\u80fd\u4f1a\u964d\u4f4e\u6027\u80fd\u3002\u60a8\u53ef\u4ee5\u5c1d\u8bd5\u6dfb\u52a0\u7d22\u5f15\u6216\u91cd\u5199\u67e5\u8be2\u4ee5\u907f\u514d\u6392\u5e8f\u3002<\/li>\n
      •  \u5982\u679c\u51fa\u73b0 Using temporary<\/strong>\uff0c\u5219\u8868\u660e\u67e5\u8be2\u6b63\u5728\u521b\u5efa\u4e34\u65f6\u8868\uff0c\u8fd9\u4e5f\u4f1a\u964d\u4f4e\u6027\u80fd\u3002\u60a8\u53ef\u4ee5\u5c1d\u8bd5\u91cd\u5199\u67e5\u8be2\u4ee5\u907f\u514d\u521b\u5efa\u4e34\u65f6\u8868\u3002<\/li>\n<\/ul>\n
        \u4ee5\u4e0a\u5c31\u662f\u8bed\u6cd5\u63d0\u793a\u600e\u4e48\u67e5\u770b\u7684\u8be6\u7ec6\u5185\u5bb9\uff0c\u66f4\u591a\u8bf7\u5173\u6ce8\u7c73\u4e91\u7f51\u5176\u5b83\u76f8\u5173\u6587\u7ae0\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"
        \u5728 mysql \u4e2d\u67e5\u770b\u8bed\u6cd5\u63d0\u793a\u7684\u65b9\u6cd5\uff1a\u4f7f\u7528 explain \u547d\u4ee4\u67e5\u770b\u67e5\u8be2\u6267\u884c\u8ba1\u5212\uff0c\u5176\u4e2d\u5305\u62ec\u8bed\u6cd5\u63d0\u793a\u3002\u5728 explain \u8f93\u51fa\u7684 extra \u5217\u4e2d\u67e5\u627e\u8bed\u6cd5\u63d0\u793a\uff0c\u5b83\u4ee5\u7279\u5b9a\u7684\u63aa\u8f9e\u51fa\u73b0\uff0c\u4f8b\u5982 “using index” \u6216 “using where”\u3002\u7406\u89e3\u8bed\u6cd5\u63d0\u793a\uff0c\u5b83\u53ef\u4ee5\u5e2e\u52a9\u60a8\u4e86\u89e3\u67e5\u8be2\u6267\u884c\u7684\u65b9\u5f0f\u5e76\u4f18\u5316\u6027\u80fd\u3002\u4f8b\u5982\uff0c\u51fa\u73b0 “using filesort” \u8868\u660e\u9700\u8981\u6dfb\u52a0\u7d22\u5f15\u6216\u91cd\u5199\u67e5\u8be2\u4ee5\u907f\u514d\u6392\u5e8f\u3002 \u5982\u4f55\u5728 MySQL \u4e2d\u67e5\u770b\u8bed\u6cd5\u63d0\u793a \u5728 MySQL \u4e2d\u67e5\u770b\u8bed\u6cd5\u63d0\u793a\u662f\u4f18\u5316\u67e5\u8be2\u6027\u80fd\u548c\u907f\u514d\u8bed\u6cd5\u9519\u8bef\u7684\u91cd\u8981\u4e00\u6b65\u3002\u4ee5\u4e0b\u65b9\u6cd5\u53ef\u5e2e\u52a9\u60a8\u67e5\u770b\u8bed\u6cd5\u63d0\u793a\uff1a \u4f7f\u7528 EXPLAIN \u547d\u4ee4 EXPLAIN \u547d\u4ee4\u663e\u793a\u6709\u5173\u67e5\u8be2\u6267\u884c\u8ba1\u5212\u7684\u4fe1\u606f\uff0c\u5176\u4e2d\u5305\u62ec\u8bed\u6cd5\u63d0\u793a\u3002\u8981\u4f7f\u7528\u5b83\uff0c\u8bf7\u5728\u67e5\u8be2\u524d\u6dfb\u52a0 EXPLAIN \u5173\u952e\u5b57\u3002\u4f8b\u5982\uff1a EXPLAIN SELECT * FROM table_name WHERE id = 1; \u767b\u5f55\u540e\u590d\u5236 \u8f93\u51fa\u89e3\u91ca EXPLAIN \u8f93\u51fa\u662f\u4e00\u4e2a\u8868\u683c\uff0c\u5305\u542b\u4ee5\u4e0b\u4fe1\u606f\uff1a id\uff1a \u5b50\u67e5\u8be2\u7684 ID select_type\uff1a \u67e5\u8be2\u7c7b\u578b\uff08\u4f8b\u5982\uff0cSIMPLE\u3001PRIMARY\uff09 table\uff1a \u8bbf\u95ee\u7684\u8868 type\uff1a \u7528\u4e8e\u8868\u4e2d\u7684\u7d22\u5f15\u7c7b\u578b\uff08\u4f8b\u5982\uff0cALL\u3001RANGE\uff09 possible_keys\uff1a \u53ef\u7528\u4e8e\u8868\u7684\u7d22\u5f15 key\uff1a […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16],"tags":[],"class_list":["post-5445","post","type-post","status-publish","format-standard","hentry","category-16"],"_links":{"self":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/5445","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/comments?post=5445"}],"version-history":[{"count":0,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/5445\/revisions"}],"wp:attachment":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/media?parent=5445"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/categories?post=5445"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/tags?post=5445"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}