{"id":209773,"date":"2022-08-18T15:53:44","date_gmt":"2022-08-18T07:53:44","guid":{"rendered":"https:\/\/www.keaglegz.com\/209773.html"},"modified":"2022-08-18T15:53:44","modified_gmt":"2022-08-18T07:53:44","slug":"mysql%e7%9a%84repeatable-read%e9%9a%94%e7%a6%bb%e7%ba%a7%e5%88%ab%e4%b8%8b%e8%af%bb%e5%8f%96%e5%88%b0%e7%9a%84%e9%87%8d%e5%a4%8d%e6%95%b0%e6%8d%ae","status":"publish","type":"post","link":"https:\/\/www.dongwubaike.cn\/fanhao\/209773.html","title":{"rendered":"MySQL\u7684REPEATABLE-READ\u9694\u79bb\u7ea7\u522b\u4e0b\u8bfb\u53d6\u5230\u7684\u201c\u91cd\u590d\u6570\u636e"},"content":{"rendered":"\n

\u5728MySQL\u4e2d\uff0c\u4f7f\u7528MVCC\u6765\u5b9e\u73b0REPEATABLE-READ\u9694\u79bb\u7ea7\u522b\uff0c\u7531\u4e8eSELECT\u64cd\u4f5c\u4e0d\u4f1a\u5bf9\u6570\u636e\u52a0\u9501\uff0c\u5176\u4ed6\u56de\u8bdd\u53ef\u4ee5\u4fee\u6539\u5f53\u524d\u56de\u8bdd\u6240\u8bfb\u53d6\u8fc7\u7684\u6570\u636e\u800c\u4e0d\u4f1a\u88ab\u963b\u585e\uff0c\u56e0\u6b64\u8bfb\u5199\u4e0d\u51b2\u7a81\u3002<\/p>\n

\u5728MVCC\u5e76\u53d1\u63a7\u5236\u4e2d\uff0c\u8bfb\u64cd\u4f5c\u53ef\u4ee5\u5206\u6210\u4e24\u7c7b\uff1a\u5feb\u7167\u8bfb (snapshot read)\u4e0e\u5f53\u524d\u8bfb (current read)\u3002\u5feb\u7167\u8bfb\uff0c\u8bfb\u53d6\u7684\u662f\u8bb0\u5f55\u7684\u53ef\u89c1\u7248\u672c (\u6709\u53ef\u80fd\u662f\u5386\u53f2\u7248\u672c)\uff0c\u4e0d\u7528\u52a0\u9501\u3002\u5f53\u524d\u8bfb\uff0c\u8bfb\u53d6\u7684\u662f\u8bb0\u5f55\u7684\u6700\u65b0\u7248\u672c\uff0c\u5e76\u4e14\uff0c\u5f53\u524d\u8bfb\u8fd4\u56de\u7684\u8bb0\u5f55\uff0c\u90fd\u4f1a\u52a0\u4e0a\u9501\uff0c\u4fdd\u8bc1\u5176\u4ed6\u4e8b\u52a1\u4e0d\u4f1a\u518d\u5e76\u53d1\u4fee\u6539\u8fd9\u6761\u8bb0\u5f55\u3002<\/p>\n

\u5f53\u4e8b\u52a1\u4e2d\u8fdb\u884c\u67e5\u8be2\u65f6\uff0cMySQL\u4f1a\u628a\u5feb\u7167\u8bfb\u548c\u5f53\u524d\u8bfb\u7684\u7ed3\u679c\u8fdb\u884c\u5408\u5e76\u518d\u8fd4\u56de\u7ed9\u5ba2\u6237\u7aef\uff0c\u800c\u8fd9\u4e2a\u5408\u5e76\u53ef\u80fd\u5bfc\u81f4\u4e00\u4e9b\u5947\u7279\u7684\u7ed3\u679c\u3002<\/p>\n

\u751f\u6210\u6d4b\u8bd5\u6570\u636e\uff1a<\/p>\n

\n
drop<\/span> table<\/span> tb002; <\/span>create<\/span> table<\/span> tb002(id int<\/span> primary<\/span> key<\/span>,c2 int<\/span>,unique<\/span> index<\/span> uni_c2(c2)); <\/span>begin<\/span>; <\/span>insert<\/span> into<\/span> tb002(id,c2) select<\/span> 1<\/span>,1<\/span>; <\/span>insert<\/span> into<\/span> tb002(id,c2) select<\/span> 2<\/span>,2<\/span>; <\/span>insert<\/span> into<\/span> tb002(id,c2) select<\/span> 4<\/span>,4<\/span>; <\/span>commit<\/span>;<\/pre>\n<\/p><\/div>\n
\u5047\u8bbe\u6709\u56de\u8bddA\u548c\u56de\u8bddB,\u5747\u4f7f\u7528REPEATABLE-READ\u9694\u79bb\u7ea7\u522b<\/p>\n
##========================================================##<\/p>\n
\u9996\u5148\u56de\u8bddA\u6267\u884cSQL\uff1a<\/p>\n
\n
begin<\/span>; <\/span>select<\/span> *<\/span> from<\/span> tb002;<\/pre>\n<\/p><\/div>\n
\u8fd4\u56de\u7ed3\u679c\u5982\u4e0b\uff1a<\/p>\n
\"MySQL\u7684REPEATABLE-READ\u9694\u79bb\u7ea7\u522b\u4e0b\u8bfb\u53d6\u5230\u7684\u201c\u91cd\u590d\u6570\u636e\"<\/a><\/p>\n
##========================================================##<\/p>\n
\u7136\u540e\u56de\u8bddB\u6267\u884cSQL\uff1a<\/p>\n
\n
begin<\/span>; <\/span>delete<\/span> from<\/span> tb002 where<\/span> id=<\/span>2<\/span>; <\/span>commit<\/span>;<\/pre>\n<\/p><\/div>\n
\u7531\u4e8e\u56de\u8bddA\u6ca1\u6709\u52a0\u9501\uff0c\u6240\u4ee5\u56de\u8bddB\u80fd\u987a\u5229\u5b8c\u6210\u5220\u9664\u5e76\u63d0\u4ea4\u4e8b\u52a1\uff0c\u5f53\u524d\u6570\u636e\u5e93\u4e2d\u65e0C2=2\u7684\u8bb0\u5f55\uff0c\u4e14\u4f1a\u8bddB\u63d0\u4ea4\u4e8b\u52a1\u91ca\u653e\u9501\u3002<\/p>\n
##========================================================##<\/p>\n
\u56de\u5230\u56de\u8bddA\u6267\u884cSQL\uff1a<\/p>\n
\n
insert<\/span> into<\/span> tb002(id,c2) select<\/span> 3<\/span>,2<\/span>; <\/span><\/pre>\n<\/p><\/div>\n
\u7531\u4e8e\u5f53\u524d\u6570\u636e\u5e93\u4e2d\u65e0C2=2\u7684\u8bb0\u5f55\uff0c\u4e14\u5176\u4ed6\u56de\u8bdd\u6ca1\u6709\u5728\u6b64C2=2\u7684\u8303\u56f4\u4e0a\u52a0\u9501\uff0c\u56e0\u6b64\u56de\u8bddA\u53ef\u4ee5\u5b8c\u6210C2=2\u7684\u6570\u636e\u63d2\u5165\u3002<\/p>\n
\u5728\u56de\u8bddA\u4e0a\u518d\u6b21\u8fdb\u884c\u67e5\u8be2\uff1a<\/p>\n
\n
select<\/span> *<\/span> from<\/span> tb002;<\/pre>\n<\/p><\/div>\n
\u8fd4\u56de\u7ed3\u679c\u5982\uff1a<\/p>\n
\"MySQL\u7684REPEATABLE-READ\u9694\u79bb\u7ea7\u522b\u4e0b\u8bfb\u53d6\u5230\u7684\u201c\u91cd\u590d\u6570\u636e\"<\/a><\/p>\n
C2\u4e0a\u6709\u552f\u4e00\u7d22\u5f15\uff0c\u4f46\u4e3a\u4ec0\u4e48\u67e5\u8be2\u7ed3\u679c\u4e2d\u4ecd\u5305\u542b\u4e24\u6761C2=2\u7684\u8bb0\u5f55\u5462\uff1fID=2\u7684\u8bb0\u5f55\u5c5e\u4e8e\u5feb\u7167\u8bfb\u7684\u6570\u636e\uff0cID=3\u7684\u8bb0\u5f55\u6570\u636e\u5f53\u524d\u8bfb\u7684\u6570\u636e\uff0cMySQL\u5c06\u5f53\u524d\u8bfb\u548c\u5feb\u7167\u8bfb\u7684\u6570\u636e\u8fdb\u884c\u7b80\u5355\u7684\u5408\u5e76\u540e\u8fd4\u56de\u7ed9\u5ba2\u6237\u7aef\uff0c\u5e76\u4e0d\u68c0\u67e5“\u7ed3\u679c\u6570\u636e\u662f\u5426\u6ee1\u8db3\u552f\u4e00\u7d22\u5f15”\u7684\u8981\u6c42\u3002<\/p>\n
##========================================================##<\/p>\n
\u4e0a\u9762\u7684\u6d4b\u8bd5\u9488\u5bf9\u552f\u4e00\u7d22\u5f15\u8fdb\u884c\uff0c\u90a3\u5982\u679c\u9488\u5bf9\u4e3b\u952e\u4f1a\u6709\u5565\u533a\u522b\u5462\uff1f<\/p>\n
\u5c06\u63d2\u5165SQL\u4fee\u6539\u4e3a\uff1a<\/p>\n
\n
insert<\/span> into<\/span> tb002(id,c2) select<\/span> 2<\/span>,3<\/span>;<\/pre>\n<\/p><\/div>\n
\u5373\u56de\u8bddB\u5220\u9664\u7684ID\u503c\u548c\u56de\u8bddA\u65b0\u63d2\u5165\u7684ID\u503c\u76f8\u540c\u60c5\u51b5\u4e0b\uff0c\u6700\u540e\u7684\u67e5\u8be2\u7ed3\u679c\u5e76\u4e0d\u4f1a\u5305\u542b\u4e24\u6761\u76f8\u540cID\u7684\u8bb0\u5f55\uff0c\u5bf9\u4e8e“\u5feb\u7167\u8bfb”\u548c“\u5f53\u524d\u8bfb”\u4e24\u4e2a\u7ed3\u679c\u96c6\u5b58\u5728”\u4e3b\u952e\u51b2\u7a81“\u7684\u60c5\u51b5\uff0c\u6700\u7ec8\u8fd4\u56de\u5ba2\u6237\u7aef\u7684\u7ed3\u679c\u4f1a”\u4e22\u5f03“\u5feb\u7167\u8bfb\u4e2d\u7684”\u8001\u7248\u672c“\u8bb0\u5f55\uff0c\u4fdd\u7559\u6700\u65b0\u7248\u672c\u7684\u8bb0\u5f55\u3002<\/p>\n
\u53ef\u89c1\u5bf9\u4e8e\u4e3b\u952e\u4e0d\u5b58\u5728\u4e0a\u8ff0\u95ee\u9898\u3002<\/p>\n
##========================================================##<\/p>\n
\u603b\u7ed3\uff1a<\/p>\n
\u5728\u57fa\u4e8eMVCC\u5b9e\u73b0\u7684REPEATABLE-READ\u9694\u79bb\u7ea7\u522b\u4e0b\uff0c\u7531\u4e8e\u5feb\u7167\u8bfb\u548c\u5f53\u524d\u8bfb\u7684\u5f71\u54cd\uff0c\u4f1a\u5bfc\u81f4\u8fd4\u56de\u6570\u636e\u7ed3\u679c\u96c6\u8d85\u8fc7”\u671f\u671b\u7ed3\u679c\u96c6“\u7684\u60c5\u51b5\uff0c\u751a\u81f3\u8fd4\u56de\u7ed3\u679c\u96c6\u4e2d\u5305\u542b\u91cd\u590d\u7684”\u552f\u4e00\u7d22\u5f15\u952e“\uff0c\u4f46\u8fd4\u56de\u7ed3\u679c\u96c6\u4e2d\u4e0d\u4f1a\u5305\u542b\u91cd\u590d\u7684“\u4e3b\u952e”\uff08PS\uff1a\u5355\u8868\u67e5\u8be2\u7684\u524d\u63d0\u4e0b\uff09\u3002<\/p>\n
\u5982\u679c\u5728\u4e8b\u52a1\u4e2d\u5305\u542b\u5148\u63d2\u5165\u540e\u67e5\u8be2\u7684\u60c5\u51b5\uff0c\u5e94\u8be5\u8003\u8651\u4e0a\u8ff0\u95ee\u9898\u5bf9\u4e1a\u52a1\u7684\u5f71\u54cd\u3002<\/p>\n
\u672c\u6587\u6c38\u4e45\u66f4\u65b0\u94fe\u63a5\u5730\u5740<\/span>\uff1ahttp:\/\/www.linuxidc.com\/Linux\/2018-02\/150769.htm<\/p>\n
\"MySQL\u7684REPEATABLE-READ\u9694\u79bb\u7ea7\u522b\u4e0b\u8bfb\u53d6\u5230\u7684\u201c\u91cd\u590d\u6570\u636e\"<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
\u5728MySQL\u4e2d\uff0c\u4f7f\u7528MVCC\u6765\u5b9e\u73b0REPEATABLE-READ\u9694\u79bb\u7ea7\u522b\uff0c\u7531\u4e8eSELECT\u64cd\u4f5c\u4e0d\u4f1a\u5bf9\u6570\u636e\u52a0\u9501\uff0c\u5176\u4ed6\u56de\u8bdd\u53ef\u4ee5\u4fee\u6539\u5f53\u524d\u56de\u8bdd\u6240\u8bfb\u53d6\u8fc7\u7684\u6570\u636e\u800c\u4e0d\u4f1a\u88ab\u963b\u585e\uff0c\u56e0\u6b64\u8bfb\u5199\u4e0d\u51b2\u7a81\u3002<\/p>\n","protected":false},"author":1,"featured_media":209772,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[],"tags":[],"class_list":["post-209773","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry"],"_links":{"self":[{"href":"https:\/\/www.dongwubaike.cn\/fanhao\/wp-json\/wp\/v2\/posts\/209773","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.dongwubaike.cn\/fanhao\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.dongwubaike.cn\/fanhao\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.dongwubaike.cn\/fanhao\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.dongwubaike.cn\/fanhao\/wp-json\/wp\/v2\/comments?post=209773"}],"version-history":[{"count":0,"href":"https:\/\/www.dongwubaike.cn\/fanhao\/wp-json\/wp\/v2\/posts\/209773\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.dongwubaike.cn\/fanhao\/wp-json\/wp\/v2\/media\/209772"}],"wp:attachment":[{"href":"https:\/\/www.dongwubaike.cn\/fanhao\/wp-json\/wp\/v2\/media?parent=209773"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.dongwubaike.cn\/fanhao\/wp-json\/wp\/v2\/categories?post=209773"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.dongwubaike.cn\/fanhao\/wp-json\/wp\/v2\/tags?post=209773"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}