{"id":210130,"date":"2022-08-22T14:21:57","date_gmt":"2022-08-22T06:21:57","guid":{"rendered":"https:\/\/www.keaglegz.com\/210130.html"},"modified":"2022-08-22T14:21:57","modified_gmt":"2022-08-22T06:21:57","slug":"oracle%e4%b8%ad%e4%bd%bf%e7%94%a8optimizer_mode%e5%8f%82%e6%95%b0%e6%84%8f%e4%b9%89","status":"publish","type":"post","link":"https:\/\/www.dongwubaike.cn\/fanhao\/210130.html","title":{"rendered":"Oracle\u4e2d\u4f7f\u7528optimizer_mode\u53c2\u6570\u610f\u4e49"},"content":{"rendered":"\n

Oracle\u4f7f\u7528Optimizer_mode\u53c2\u6570\u6765\u63a7\u5236\u4f18\u5316\u5668\u7684\u504f\u597d\uff0c9i\u5e38\u7528\u7684\u51e0\u4e2a\u53c2\u6570\u6709:first_rows,all_rows,first_rows_N,rule,choose\u7b49\u3002\u800c10g\u5c11\u4e86rule\u548cchoose.Oracle \u5728\u6267\u884cSQL\u8bed\u53e5\u65f6\uff0c\u6709\u4e24\u79cd\u4f18\u5316\u65b9\u6cd5\uff1a\u5373\u57fa\u4e8e\u89c4\u5219\u7684RBO\u548c\u57fa\u4e8e\u4ee3\u4ef7\u7684CBO\u3002 \u5728SQL\u6267\u884c\u7684\u65f6\u5019\uff0c\u5230\u5e95\u91c7\u7528\u4f55\u79cd\u4f18\u5316\u65b9\u6cd5\uff0c\u5c31\u7531Oracle\u53c2\u6570 optimizer_mode \u6765\u51b3\u5b9a\u3002<\/p>\n

Rule Based Optimizer\uff08RBO\uff09\u57fa\u4e8e\u89c4\u5219
Cost Based Optimizer\uff08CBO\uff09\u57fa\u4e8e\u6210\u672c\uff0c\u6216\u8005\u8bb2\u7edf\u8ba1\u4fe1\u606f<\/p>\n

SQL> show parameter optimizer_mode;<\/p>\n

NAME TYPE VALUE<\/p>\n

optimizer_mode string ALL_ROWS<\/p>\n

oracle10g\u5f00\u59cb\u9ed8\u8ba4\u662fall_rows<\/p>\n

ALL_ROWS\u4e0d\u7ba1\u662f\u4e0d\u662f\u6709\u7edf\u8ba1\u4fe1\u606f\uff0c\u5168\u90e8\u91c7\u7528\u57fa\u4e8e\u6210\u672c\u7684\u4f18\u5316\u65b9\u6cd5\uff0c\u8fd4\u56de\u6700\u5927\u6570\u7684\u91cf\u6570\u636e<\/p>\n

FIRST_ROWS_n\u4e0d\u7ba1\u662f\u4e0d\u662f\u6709\u7edf\u8ba1\u4fe1\u606f\uff0c\u5168\u90e8\u91c7\u7528\u57fa\u4e8e\u6210\u672c\u7684\u4f18\u5316\u65b9\u6cd5\u5e76\u4ee5\u6700\u5feb\u7684\u901f\u5ea6\uff0c\u8fd4\u56de\u524dN\u884c\u8bb0\u5f55<\/p>\n

FIRST_ROWS\u4f7f\u7528\u6210\u672c\u548c\u8bd5\u63a2\u6cd5\u76f8\u7ed3\u5408\u7684\u65b9\u6cd5\uff0c\u67e5\u627e\u4e00\u79cd\u53ef\u4ee5\u6700\u5feb\u8fd4\u56de\u524d\u9762\u5c11\u6570\u884c\u7684\u65b9\u6cd5<\/p>\n

\u7b2c\u4e00\u4e2a\u662f\u8fd4\u56de\u6240\u6709\u884c\u7684\u6700\u5c0f\u4ee3\u4ef7\uff0c\u7b2c\u4e8c\u4e2a\u662f\u8fd4\u56de\u524dN\u884c\u7684\u6700\u5c0f\u4ee3\u4ef7\uff0c\u6700\u540e\u4e00\u4e2a\u662f\u8fd4\u56de\u524d\u9762\u7684\u5c11\u91cf\u884c\u7684\u6700\u597d\u8ba1\u5212<\/p>\n

\u4fee\u6539\u5168\u5c40
alter system set optimizer_mode=all_rows;<\/p>\n

\u4fee\u6539\u5f53\u524dsession<\/p>\n

alter session set optimizer_mode=all_rows;<\/p>\n

\u51e0\u4e2a\u53c2\u6570\u7684\u5177\u4f53\u89e3\u91ca\uff1a<\/strong><\/p>\n

optimizer_mode =choose
\u8fd9\u4e2a\u662fOracle\u7684\u9ed8\u8ba4\u503c\u3002\u91c7\u7528\u8fd9\u4e2a\u503c\u65f6\uff0cOracle\u5373\u53ef\u4ee5\u91c7\u7528\u57fa\u4e8e\u89c4\u5219RBO\uff0c\u4e5f\u53ef\u4ee5\u91c7\u7528\u57fa\u4e8e\u4ee3\u4ef7\u7684CBO\uff0c\u5230\u5e95\u4f7f\u7528\u90a3\u4e2a\u503c\uff0c\u53d6\u51b3\u4e8e\u5f53\u524dSQL\u7684\u88ab\u8bbf\u95ee\u7684\u8868\u4e2d\u662f\u4e0d\u662f\u6709\u53ef\u4ee5\u4f7f\u7528\u7684\u7edf\u8ba1\u4fe1\u606f\u3002\u5982\u679c\u6709\u591a\u4e2a\u88ab\u8bbf\u95ee\u7684\u8868\uff0c\u5176\u4e2d\u6709\u4e00\u4e2a\u6216\u591a\u4e2a\u6709\u7edf\u8ba1\u4fe1\u606f\uff0c\u90a3\u4e48Oralce\u4f1a\u5bf9\u6ca1\u6709\u7edf\u8ba1\u4fe1\u606f\u7684\u8868\u8fdb\u884c\u91c7\u6837\u7edf\u8ba1\uff08\u5373\u4e0d\u5168\u90e8\u91c7\u6837\uff09\uff0c\u7edf\u8ba1\u5b8c\u6210\u540e\uff0c\u4f7f\u7528\u57fa\u4e8e\u4ee3\u4ef7\u7684\u4f18\u5316\u65b9\u6cd5CBO\u3002\u5982\u679c\u6240\u6709\u88ab\u8bbf\u95ee\u7684\u8868\u90fd\u6ca1\u6709\u7edf\u8ba1\u4fe1\u606f\uff0cOracle\u5c31\u4f1a\u91c7\u7528\u57fa\u4e8e\u89c4\u5219\u7684\u4f18\u5316\u65b9\u6cd5RBO\u3002<\/p>\n

Optimizer_mode=First_rows
\u5728oracle 9i\u4e4b\u540e\u8fd9\u4e00\u9009\u9879\u5df2\u7ecf\u8fc7\u65f6\uff0c\u51fa\u4e8e\u5411\u540e\u517c\u5bb9\u7684\u76ee\u7684\u4fdd\u7559\u4e86\u8fd9\u4e00\u9009\u9879\uff0c\u8be5\u9009\u9879\u7684\u4f5c\u7528\u5728\u4e8e\u5bfb\u627e\u80fd\u591f\u5728\u6700\u77ed\u7684\u65f6\u95f4\u5185\u8fd4\u56de\u7ed3\u679c\u96c6\u7684\u7b2c\u4e00\u884c\u7684\u6267\u884c\u8ba1\u5212\u3002\u8fd9\u4e00\u89c4\u5219\u503e\u5411\u4e8e\u4fc3\u4f7f\u4f18\u5316\u5668\u4f7f\u7528\u7d22\u5f15\u8bbf\u95ee\u8def\u5f84\uff0c\u5076\u5c14\u4f1a\u51fa\u73b0\u975e\u5e38\u4e0d\u6070\u5f53\u7684\u8bbf\u95ee\u8def\u5f84\u3002<\/p>\n

\u8bbe\u7f6e\u4e3a\u8fd9\u79cdCBO\u6a21\u5f0f\u4ee5\u540e\uff0cSQL\u8bed\u53e5\u8fd4\u56de\u7ed3\u679c\u7684\u901f\u5ea6\u4f1a\u5c3d\u53ef\u80fd\u7684\u5feb\uff0c\u800c\u4e0d\u7ba1\u7cfb\u7edf\u5168\u90e8\u7684\u67e5\u8be2\u662f\u5426\u4f1a\u8017\u65f6\u8f83\u957f\u6216\u8005\u8017\u7cfb\u7edf\u8d44\u6e90\u8fc7\u591a\u3002\u7531\u4e8e\u5229\u7528\u7d22\u5f15\u4f1a\u4f7f\u67e5\u8be2\u901f\u5ea6\u52a0\u5feb\uff0c\u6240\u4ee5 first_rows \u4f18\u5316\u6a21\u5f0f\u4f1a\u5728\u5168\u8868\u626b\u63cf\u4e0a\u8fdb\u884c\u7d22\u5f15\u626b\u63cf\u3002\u8fd9\u79cd\u4f18\u5316\u6a21\u5f0f\u4e00\u822c\u9002\u5408\u4e8e\u4e00\u4e9bOLTP\u7cfb\u7edf\uff0c\u6ee1\u8db3\u7528\u6237\u80fd\u591f\u5728\u8f83\u77ed\u65f6\u95f4\u5185\u770b\u5230\u8f83\u5c0f\u67e5\u8be2\u7ed3\u679c\u96c6\u7684\u8981\u6c42\u3002<\/p>\n

Optimizer_mode=all_rows
\u4f18\u5316\u5668\u5c06\u5bfb\u627e\u80fd\u591f\u5728\u6700\u77ed\u7684\u65f6\u95f4\u5185\u5b8c\u6210\u8bed\u53e5\u7684\u6267\u884c\u8ba1\u5212\u3002
\u8bbe\u7f6e\u4e3a\u8fd9\u79cdCBO\u6a21\u5f0f\u4ee5\u540e\uff0c\u5c06\u4fdd\u8bc1\u6d88\u8017\u7684\u6240\u6709\u8ba1\u7b97\u8d44\u6e90\u6700\u5c0f\uff0c\u5c3d\u7ba1\u6709\u65f6\u67e5\u8be2\u7ed3\u675f\u4ee5\u540e\u6ca1\u6709\u7ed3\u679c\u8fd4\u56de\u3002all_rows \u7684\u4f18\u5316\u6a21\u5f0f\u66f4\u503e\u5411\u4e8e\u5168\u8868\u626b\u63cf\uff0c\u800c\u4e0d\u662f\u5168\u7d22\u5f15\u626b\u63cf\u548c\u5229\u7528\u7d22\u5f15\u6392\u5e8f\uff0c\u56e0\u6b64\u8fd9\u79cd\u4f18\u5316\u6a21\u5f0f\u9002\u5408\u4e8e\u6570\u636e\u67e5\u770b\u5b9e\u65f6\u6027\u4e0d\u662f\u90a3\u4e48\u5f3a\u7684\u6570\u636e\u4ed3\u5e93\u3001\u51b3\u7b56\u652f\u6301\u7cfb\u7edf\u548c\u9762\u5411\u6279\u5904\u7406\u7684\u6570\u636e\u5e93\uff08batch-oriented databases\uff09\u7b49\u3002<\/p>\n

Optimizer_mode=first_rows_N
N\u7684\u503c\u53ef\u4ee5\u4e3a1\uff0c10\uff0c100\uff0c1000\uff0c\u4f18\u5316\u5668\u9996\u5148\u901a\u8fc7\u5f7b\u5e95\u5206\u6790\u7b2c\u4e00\u4e2a\u8fde\u63a5\u987a\u5e8f\u6765\u4f30\u8ba1\u8fd4\u56de\u884c\u7684\u603b\u6570\u76ee\u3002\u8fd9\u6837\u5c31\u53ef\u4ee5\u77e5\u9053\u67e5\u8be2\u53ef\u80fd\u83b7\u5f97\u7684\u6574\u4e2a\u6570\u636e\u96c6\u7684\u7247\u6bb5\uff0c\u5e76\u91cd\u65b0\u542f\u52a8\u6574\u4e2a\u4f18\u5316\u8fc7\u7a0b\uff0c\u5176\u76ee\u6807\u5728\u4e8e\u627e\u5230\u80fd\u591f\u4ee5\u6700\u5c0f\u7684\u8d44\u6e90\u6d88\u8017\u8fd4\u56de\u6574\u4e2a\u6570\u636e\u7247\u6bb5\u7684\u6267\u884c\u8ba1\u5212\u3002<\/p>\n

Oracle 9i \u5bf9\u4e00\u4e9b\u9884\u671f\u8fd4\u56de\u7ed3\u679c\u96c6\u7684\u6570\u636e\u91cf\u5c0f\u7684SQL\u8bed\u53e5\u4f18\u5316\u6a21\u5f0f\u8fdb\u884c\u4e86\u52a0\u5f3a\uff0c\u589e\u52a0\u4e86\u56db\u4e2a\u53c2\u6570\u503c\uff1afirst_rows_1\u3001first_rows_10\u3001 first_rows_100\u3001first_rows_1000\u3002CBO\u901a\u8fc7first_rows_n \u4e2d\u7684 n \u503c\uff0c\u51b3\u5b9a\u4e86\u8fd4\u56de\u7ed3\u679c\u96c6\u6570\u91cf\u7684\u57fa\u6570\uff0c\u6211\u4eec\u53ef\u80fd\u4ec5\u4ec5\u9700\u8981\u67e5\u8be2\u7ed3\u679c\u96c6\u4e2d\u7684\u4e00\u90e8\u5206\uff0cCBO\u5c31\u6839\u636e\u8fd9\u6837\u7684 n \u503c\u6765\u51b3\u5b9a\u662f\u5426\u4f7f\u7528\u7d22\u5f15\u626b\u63cf\u3002<\/p>\n

optimizer_mode = rule
\u57fa\u4e8e\u89c4\u5219\u7684\u4f18\u5316\u5668\u6a21\u5f0f\uff0cRBO\uff0c\u662f\u65e9\u671fOracle\u7248\u672c\u4f7f\u7528\u8fc7\u7684\u4e00\u79cd\u4f18\u5316\u6a21\u5f0f\u3002\u7531\u4e8e RBO\u4e0d\u652f\u6301\u81ea1994\u5e74Oracle\u7248\u672c\u7684\u65b0\u7279\u6027\uff0c\u5982 bitmap indexes\uff0ctable partitions\uff0cfunction-based indexes\u7b49\uff0c\u6240\u4ee5\u5728\u4ee5\u540eOracle\u7248\u672c\u4e2d\u5df2\u7ecf\u4e0d\u518d\u66f4\u65b0RBO\uff0c\u5e76\u4e14\u4e5f\u4e0d\u63a8\u8350\u7528\u6237\u4f7f\u7528RBO\u8fd9\u79cd\u4f18\u5316\u6a21\u5f0f\u4e86\u3002<\/p>\n

\u66f4\u591aOracle\u76f8\u5173\u4fe1\u606f\u89c1<\/span>Oracle<\/span> \u4e13\u9898\u9875\u9762 <\/span>http:\/\/www.linuxidc.com\/topicnews.aspx?tid=12<\/span><\/span><\/p>\n

\u672c\u6587\u6c38\u4e45\u66f4\u65b0\u94fe\u63a5\u5730\u5740<\/strong><\/span>\uff1ahttp:\/\/www.linuxidc.com\/Linux\/2018-01\/150041.htm<\/p>\n

\"Oracle\u4e2d\u4f7f\u7528optimizer_mode\u53c2\u6570\u610f\u4e49\"<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Oracle\u4f7f\u7528Optimizer_mode\u53c2\u6570\u6765\u63a7\u5236\u4f18\u5316\u5668\u7684\u504f\u597d\uff0c9i\u5e38\u7528\u7684\u51e0\u4e2a\u53c2\u6570\u6709:first_rows,all_rows,first_rows_N,rule,choose\u7b49\u3002\u800c10g\u5c11\u4e86rule\u548cchoose.Oracle \u5728\u6267\u884cSQL\u8bed\u53e5\u65f6\uff0c\u6709\u4e24\u79cd\u4f18\u5316\u65b9\u6cd5\uff1a\u5373\u57fa\u4e8e\u89c4\u5219\u7684RBO\u548c\u57fa\u4e8e\u4ee3\u4ef7\u7684CBO\u3002 \u5728SQL\u6267\u884c\u7684\u65f6\u5019\uff0c\u5230\u5e95\u91c7\u7528\u4f55\u79cd\u4f18\u5316\u65b9\u6cd5\uff0c\u5c31\u7531Oracle\u53c2\u6570 optimizer_mode \u6765\u51b3\u5b9a\u3002<\/p>\n","protected":false},"author":2,"featured_media":210131,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[],"tags":[],"class_list":["post-210130","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry"],"_links":{"self":[{"href":"https:\/\/www.dongwubaike.cn\/fanhao\/wp-json\/wp\/v2\/posts\/210130","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\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.dongwubaike.cn\/fanhao\/wp-json\/wp\/v2\/comments?post=210130"}],"version-history":[{"count":0,"href":"https:\/\/www.dongwubaike.cn\/fanhao\/wp-json\/wp\/v2\/posts\/210130\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.dongwubaike.cn\/fanhao\/wp-json\/wp\/v2\/media\/210131"}],"wp:attachment":[{"href":"https:\/\/www.dongwubaike.cn\/fanhao\/wp-json\/wp\/v2\/media?parent=210130"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.dongwubaike.cn\/fanhao\/wp-json\/wp\/v2\/categories?post=210130"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.dongwubaike.cn\/fanhao\/wp-json\/wp\/v2\/tags?post=210130"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}