{"id":2074,"date":"2024-05-25T11:04:27","date_gmt":"2024-05-25T03:04:27","guid":{"rendered":"http:\/\/oneai.eu.org\/?p=2074"},"modified":"2024-05-25T11:15:09","modified_gmt":"2024-05-25T03:15:09","slug":"%e8%be%be%e6%a2%a6-sql%e8%b0%83%e4%bc%98","status":"publish","type":"post","link":"https:\/\/oneai.eu.org\/?p=2074","title":{"rendered":"\u8fbe\u68a6-SQL\u8c03\u4f18"},"content":{"rendered":"<div>\n<h2 id=\"23-1-\u7b80\u4ecb\" class=\"article-heading\" style=\"position: relative;\">23.1 \u7b80\u4ecb<a class=\"article-anchor\" href=\"#23.1 \u7b80\u4ecb\" aria-hidden=\"true\"><\/a><\/p>\n<div id=\"23.1 \u7b80\u4ecb\" style=\"position: absolute; top: -100px;\"><\/div>\n<\/h2>\n<p>SQL \u8c03\u4f18\u4f5c\u4e3a\u6570\u636e\u5e93\u6027\u80fd\u8c03\u4f18\u4e2d\u7684\u6700\u540e\u4e00\u4e2a\u73af\u8282\uff0c\u5bf9\u67e5\u8be2\u6027\u80fd\u4ea7\u751f\u7740\u76f4\u63a5\u7684\u5f71\u54cd\u3002\u5728\u8fdb\u884c\u6b63\u5f0f\u7684 SQL \u8c03\u4f18\u524d\uff0c\u7528\u6237\u9996\u5148\u8981\u5173\u6ce8\u4e0b\u5217\u51e0\u70b9\uff1a<\/p>\n<ol>\n<li>\u8fbe\u68a6\u6570\u636e\u5e93\u5b89\u88c5\u65f6\u7684\u914d\u7f6e\u53c2\u6570\u662f\u5426\u7b26\u5408\u5e94\u7528\u573a\u666f\u9700\u6c42\uff1b<\/li>\n<li>\u8fbe\u68a6\u6570\u636e\u5e93\u7684 INI \u914d\u7f6e\u6587\u4ef6\u4e2d\u5404\u9879\u53c2\u6570\u662f\u5426\u5df2\u7ecf\u5904\u4e8e\u6700\u4f18\u914d\u7f6e\uff1b<\/li>\n<li>\u5e94\u7528\u7cfb\u7edf\u4e2d\u6570\u636e\u5e93\u8bbe\u8ba1\u662f\u5426\u5408\u7406\u3002<\/li>\n<\/ol>\n<p>\u672c\u7ae0\u5c06\u4ecb\u7ecd\u5b9a\u4f4d\u9ad8\u8d1f\u8f7d\u7684 SQL \u8bed\u53e5\u7684\u65b9\u6cd5\uff0c\u5229\u7528\u81ea\u52a8 SQL \u8c03\u6574\u529f\u80fd\u8fdb\u884c\u4f18\u5316\uff0c\u4ee5\u53ca\u5982\u4f55\u5f00\u53d1\u6709\u6548\u7684 SQL \u8bed\u53e5\u548c\u4f7f\u7528\u4f18\u5316\u5668\u63d0\u793a\u6765\u5f71\u54cd\u6267\u884c\u8ba1\u5212\u3002<\/p>\n<h2 id=\"23-2-\u8c03\u4f18\u76ee\u6807\" class=\"article-heading\" style=\"position: relative;\">23.2 \u8c03\u4f18\u76ee\u6807<a class=\"article-anchor\" href=\"#23.2 \u8c03\u4f18\u76ee\u6807\" aria-hidden=\"true\"><\/a><\/p>\n<div id=\"23.2 \u8c03\u4f18\u76ee\u6807\" style=\"position: absolute; top: -100px;\"><\/div>\n<\/h2>\n<p>SQL \u8c03\u4f18\u7684\u6574\u4f53\u76ee\u6807\u662f\u4f7f\u7528\u6700\u4f18\u7684\u6267\u884c\u8ba1\u5212\uff0c\u8fd9\u610f\u5473\u7740 IO \u4ee5\u53ca CPU \u4ee3\u4ef7\u6700\u5c0f\u3002\u5177\u4f53\u800c\u8a00\u8c03\u4f18\u4e3b\u8981\u5173\u6ce8\u4e0b\u5217\u65b9\u9762\uff1a<\/p>\n<ul>\n<li><strong>\u8868\u626b\u63cf<\/strong><\/li>\n<\/ul>\n<p>\u5982\u679c\u8ba1\u5212\u4e2d\u5bf9\u67d0\u5927\u8868\u4f7f\u7528\u4e86\u5168\u7d22\u5f15\u626b\u63cf\uff0c\u90a3\u4e48\u7528\u6237\u9700\u8981\u5173\u6ce8\u662f\u5426\u5b58\u5728\u7740\u8be5\u8868\u7684\u67d0\u4e2a\u67e5\u8be2\u6761\u4ef6\u4f7f\u5f97\u8fc7\u6ee4\u540e\u53ef\u4ee5\u6dd8\u6c70\u81f3\u5c11\u4e00\u534a\u7684\u6570\u636e\u91cf\u3002\u901a\u8fc7\u6dfb\u52a0\u76f8\u5e94\u7684\u7d22\u5f15\uff0c\u5168\u7d22\u5f15\u626b\u63cf\u53ef\u80fd\u88ab\u8f6c\u6362\u4e3a\u8303\u56f4\u626b\u63cf\u6216\u7b49\u503c\u67e5\u627e\u3002\u6dfb\u52a0\u7684\u4e8c\u7ea7\u7d22\u5f15\u53ef\u4ee5\u5305\u542b\u8be5\u8868\u4e0a\u6240\u6709\u88ab\u9009\u62e9\u9879\u4ee5\u907f\u514d BLKUP2 \u64cd\u4f5c\u7b26\u7684\u67e5\u627e\u64cd\u4f5c\u5e26\u6765\u7684\u7b2c\u4e8c\u6b21 IO \u5f00\u9500\uff0c\u4f46\u65e0\u7591\u8fd9\u4f1a\u589e\u52a0\u4e8c\u7ea7\u7d22\u5f15\u7684\u5927\u5c0f\u3002\u7528\u6237\u9700\u6743\u8861\u4e8c\u8005\u7684\u5229\u5f0a\u4ee5\u9009\u62e9\u6b63\u786e\u7684\u5904\u7406\u65b9\u5f0f\u3002<\/p>\n<ul>\n<li><strong>\u8fde\u63a5\u64cd\u4f5c\u7684\u987a\u5e8f\u548c\u7c7b\u578b<\/strong><\/li>\n<\/ul>\n<p>\u591a\u8868\u8fde\u63a5\u65f6\uff0c\u4e0d\u540c\u7684\u8fde\u63a5\u987a\u5e8f\u4f1a\u5f71\u54cd\u4e2d\u95f4\u7ed3\u679c\u96c6\u6570\u91cf\u7684\u5927\u5c0f\uff0c\u8fd9\u65f6\u8c03\u4f18\u7684\u76ee\u6807\u5c31\u662f\u8981\u627e\u5230\u4e00\u79cd\u80fd\u4f7f\u4e2d\u95f4\u7ed3\u679c\u4fdd\u6301\u6700\u5c0f\u7684\u8fde\u63a5\u987a\u5e8f\u3002<\/p>\n<p>\u5bf9\u4e8e\u7ed9\u5b9a\u7684\u4e00\u4e2a\u8fde\u63a5\u6216\u534a\u8fde\u63a5\uff0cDM \u53ef\u4ee5\u7528 HASH \u8fde\u63a5\u3001\u5d4c\u5957\u5faa\u73af\u8fde\u63a5\u3001\u7d22\u5f15\u8fde\u63a5\u6216\u8005\u662f\u5f52\u5e76\u8fde\u63a5\u5b9e\u73b0\u3002\u901a\u8fc7\u5206\u6790\u8868\u7684\u6570\u636e\u91cf\u5927\u5c0f\u548c\u7d22\u5f15\u4fe1\u606f\uff0cSQL \u8c03\u4f18\u76ee\u6807\u662f\u9009\u62e9\u6700\u9002\u5b9c\u7684\u64cd\u4f5c\u7b26\u3002<\/p>\n<p>\u5bf9\u534a\u8fde\u63a5\u800c\u8a00\uff0cHASH \u8fde\u63a5\u8fd8\u53ef\u7ec6\u5206\u4e3a\u5de6\u534a HASH \u548c\u53f3\u534a HASH\u3002\u7528\u6237\u53ef\u4ee5\u901a\u8fc7\u59cb\u7ec8\u5bf9\u6570\u636e\u91cf\u5c0f\u7684\u4e00\u4fa7\u5efa\u7acb HASH \u6765\u8fdb\u884c\u8c03\u4f18\u3002<\/p>\n<ul>\n<li><strong>\u5206\u7ec4\u64cd\u4f5c<\/strong><\/li>\n<\/ul>\n<p>\u5206\u7ec4\u64cd\u4f5c\u5f80\u5f80\u8981\u6c42\u7f13\u5b58\u6240\u6709\u6570\u636e\u4ee5\u627e\u5230\u5c5e\u4e8e\u540c\u4e00\u7ec4\u7684\u6240\u6709\u6570\u636e\uff0c\u5728\u5927\u6570\u636e\u91cf\u60c5\u51b5\u4e0b\u8fd9\u4f1a\u5e26\u6765\u5927\u91cf\u7684 IO\u3002\u7528\u6237\u5e94\u8be5\u68c0\u67e5 SQL \u67e5\u8be2\u548c\u8868\u4e0a\u7d22\u5f15\u4fe1\u606f\uff0c\u5982\u679c\u53ef\u4ee5\u5229\u7528\u5305\u542b\u5206\u7ec4\u5217\u7684\u7d22\u5f15\uff0c\u90a3\u4e48\u6267\u884c\u8ba1\u5212\u5c31\u4f1a\u4f7f\u7528\u6392\u5e8f\u5206\u7ec4\u4ece\u800c\u4e0d\u7528\u7f13\u5b58\u4e2d\u95f4\u7ed3\u679c\u3002<\/p>\n<h2 id=\"23-3-\u786e\u5b9a\u9ad8\u8d1f\u8f7d\u7684SQL\" class=\"article-heading\" style=\"position: relative;\">23.3 \u786e\u5b9a\u9ad8\u8d1f\u8f7d\u7684 SQL<a class=\"article-anchor\" href=\"#23.3 \u786e\u5b9a\u9ad8\u8d1f\u8f7d\u7684 SQL\" aria-hidden=\"true\"><\/a><\/p>\n<div id=\"23.3 \u786e\u5b9a\u9ad8\u8d1f\u8f7d\u7684 SQL\" style=\"position: absolute; top: -100px;\"><\/div>\n<\/h2>\n<p>\u5728\u6253\u5f00\u76d1\u63a7\u5f00\u5173\uff08ENABLE_MONITOR=1\uff09\u540e\uff0c\u53ef\u4ee5\u901a\u8fc7\u67e5\u8be2\u52a8\u6001\u89c6\u56fe V$LONG_EXEC_SQLS \u6216 V$SYSTEM_LONG_EXEC_SQLS \u6765\u786e\u5b9a\u9ad8\u8d1f\u8f7d\u7684 SQL \u8bed\u53e5\u3002\u524d\u8005\u663e\u793a\u6700\u8fd1 1000 \u6761\u6267\u884c\u65f6\u95f4\u8f83\u957f\u7684 SQL \u8bed\u53e5\uff0c\u540e\u8005\u663e\u793a\u670d\u52a1\u5668\u542f\u52a8\u4ee5\u6765\u6267\u884c\u65f6\u95f4\u6700\u957f\u7684 20 \u6761 SQL \u8bed\u53e5\u3002\u4f8b\u5982\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">  SELECT * FROM V$LONG_EXEC_SQLS;\n<\/code><\/pre>\n<p>\u6216\u8005<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">  SELECT * FROM V$SYSTEM_LONG_EXEC_SQLS;\n<\/code><\/pre>\n<h2 id=\"23-4-\u81ea\u52a8SQL\u8c03\u6574\" class=\"article-heading\" style=\"position: relative;\">23.4 \u81ea\u52a8 SQL \u8c03\u6574<a class=\"article-anchor\" href=\"#23.4 \u81ea\u52a8 SQL \u8c03\u6574\" aria-hidden=\"true\"><\/a><\/p>\n<div id=\"23.4 \u81ea\u52a8 SQL \u8c03\u6574\" style=\"position: absolute; top: -100px;\"><\/div>\n<\/h2>\n<p>\u4f7f\u7528\u67e5\u8be2\u4f18\u5316\u5411\u5bfc\u5de5\u5177\uff0c\u8f93\u5165\u9700\u8981\u8fdb\u884c\u8c03\u6574\u7684 SQL \u8bed\u53e5\uff0c\u5411\u5bfc\u5de5\u5177\u5c06\u5728\u5206\u6790\u5b8c\u6267\u884c\u8ba1\u5212\u540e\u7ed9\u51fa\u63a8\u8350\u7d22\u5f15\u7684\u63d0\u793a\u3002\u7528\u6237\u53ea\u9700\u6309\u63d0\u793a\u5efa\u7acb\u76f8\u5e94\u7d22\u5f15\u5373\u53ef\u3002<\/p>\n<h2 id=\"23-5-\u5f00\u53d1\u6709\u6548\u7684SQL\u8bed\u53e5\" class=\"article-heading\" style=\"position: relative;\">23.5 \u5f00\u53d1\u6709\u6548\u7684 SQL \u8bed\u53e5<a class=\"article-anchor\" href=\"#23.5 \u5f00\u53d1\u6709\u6548\u7684 SQL \u8bed\u53e5\" aria-hidden=\"true\"><\/a><\/p>\n<div id=\"23.5 \u5f00\u53d1\u6709\u6548\u7684 SQL \u8bed\u53e5\" style=\"position: absolute; top: -100px;\"><\/div>\n<\/h2>\n<p>SQL \u8bed\u8a00\u662f\u4e00\u79cd\u76f8\u5f53\u7075\u6d3b\u7684\u7ed3\u6784\u5316\u67e5\u8be2\u8bed\u8a00\u3002\u7528\u6237\u53ef\u4ee5\u5229\u7528\u591a\u79cd\u4e0d\u540c\u5f62\u5f0f\u7684\u67e5\u8be2\u8bed\u53e5\u5b8c\u6210\u76f8\u540c\u7684\u67e5\u8be2\u529f\u80fd\u3002\u4e3a\u4e86\u4f7f\u6267\u884c\u6548\u7387\u8fbe\u5230\u6700\u4f18\uff0c\u7528\u6237\u9700\u8981\u53c2\u8003\u4ee5\u4e0b\u539f\u5219\u4ee5\u5f00\u53d1\u51fa\u6709\u6548\u7684 SQL \u8bed\u53e5\uff1a<\/p>\n<ol>\n<li><strong>\u907f\u514d\u4f7f\u7528 OR \u5b50\u53e5<\/strong><\/li>\n<\/ol>\n<p>OR \u5b50\u53e5\u5728\u5b9e\u9645\u6267\u884c\u4e2d\u4f1a\u88ab\u8f6c\u6362\u4e3a\u7c7b\u4f3c\u4e8e UNION \u7684\u67e5\u8be2\u3002\u5982\u679c\u67d0\u4e00\u4e2a OR \u5b50\u53e5\u4e0d\u80fd\u5229\u7528\u4e0a\u7d22\u5f15\u5219\u4f1a\u4f7f\u7528\u5168\u8868\u626b\u63cf\u9020\u6210\u6548\u7387\u4f4e\u4e0b\uff0c\u5e94\u907f\u514d\u4f7f\u7528\u3002<\/p>\n<p>\u5982\u679c OR \u5b50\u53e5\u90fd\u662f\u5bf9\u540c\u4e00\u5217\u8fdb\u884c\u8fc7\u6ee4\uff0c\u7528\u6237\u53ef\u4ee5\u8003\u8651\u4f7f\u7528 IN VALUE LIST \u7684\u8fc7\u6ee4\u5f62\u5f0f\u3002\u5982\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">  SELECT ... WHERE city = 'ShangHai' OR city = 'WuHan' OR city = 'BeiJing';\n<\/code><\/pre>\n<p>\u8c03\u6574\u4e3a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">  SELECT ... WHERE city IN( 'ShangHai','WuHan','BeiJing');\n<\/code><\/pre>\n<ol start=\"2\">\n<li><strong>\u907f\u514d\u4f7f\u7528\u56f0\u96be\u7684\u6b63\u5219\u8868\u8fbe\u5f0f<\/strong><\/li>\n<\/ol>\n<p>\u5728 SQL \u8bed\u8a00\u4e2d\uff0cLIKE \u5173\u952e\u5b57\u652f\u6301\u901a\u914d\u7b26\u5339\u914d\uff0c\u542b\u901a\u914d\u7b26\u7684\u8868\u8fbe\u5f0f\u88ab\u79f0\u4e3a\u6b63\u5219\u8868\u8fbe\u5f0f\u3002\u6709\u7684\u6b63\u5219\u8868\u8fbe\u5f0f\u53ef\u4ee5\u81ea\u52a8\u4f18\u5316\u4e3a\u975e\u5339\u914d\u7684\u3002\u4f8b\u5982\uff1aa LIKE 'L%'\u53ef\u4ee5\u4f18\u5316\u4e3a a&gt;='L' AND a &lt;'M',\u8fd9\u6837\u5c31\u53ef\u4ee5\u7528\u5230 a \u4e0a\u7684\u7d22\u5f15\u3002\u5373\u4f7f\u6ca1\u6709\u7d22\u5f15\uff0c\u8f6c\u6362\u540e\u7684\u6bd4\u8f83\u4e5f\u66f4\u5feb\u3002\u518d\u5982\uff1aa LIKE 'LM_'\u53ef\u4ee5\u8f6c\u5316\u4e3a a&gt;='LM' AND a&lt;'LN' AND a LIKE 'LM_'\u3002\u867d\u7136\u4ecd\u7136\u5305\u542b\u7740\u901a\u914d\u7b26\u5339\u914d\uff0c\u4f46\u5927\u5927\u7f29\u5c0f\u4e86\u5339\u914d\u7684\u8303\u56f4\u3002<\/p>\n<p>\u6240\u8c13\u56f0\u96be\u7684\u6b63\u5219\u8868\u8fbe\u5f0f\u662f\u6307\u5f00\u5934\u548c\u7ed3\u5c3e\u90fd\u4e3a\u901a\u914d\u7b26\u7684\u6b63\u5219\u8868\u8fbe\u5f0f\uff0c\u5982'<em>L%'\u3001'%L<\/em>'\uff0c\u4f18\u5316\u5668\u6ca1\u529e\u6cd5\u7f29\u5c0f\u5b83\u4eec\u7684\u5339\u914d\u8303\u56f4\uff0c\u4e5f\u4e0d\u53ef\u80fd\u7528\u5230\u7d22\u5f15\u800c\u5fc5\u987b\u4f7f\u7528\u5168\u8868\u626b\u63cf\u3002\u56e0\u6b64\u8981\u5c3d\u53ef\u80fd\u907f\u514d\u8fd9\u6837\u7684\u6b63\u5219\u8868\u8fbe\u5f0f\u3002<\/p>\n<p>\u5982\u679c\u4ec5\u4ec5\u662f\u5f00\u5934\u4e3a\u901a\u914d\u7b26\uff0c\u7528\u6237\u53ef\u4ee5\u5728\u5217 a \u4e0a\u5efa\u7acb REVERSE(a)\u8fd9\u6837\u4e00\u4e2a\u51fd\u6570\u7d22\u5f15\uff0c\u5229\u7528\u51fd\u6570\u7d22\u5f15\u53cd\u8f6c\u5f85\u5339\u914d\u9879\u4ece\u800c\u4f7f\u7528\u51fd\u6570\u7d22\u5f15\u8fdb\u884c\u8303\u56f4\u626b\u63cf\u3002<\/p>\n<ol start=\"3\">\n<li><strong>\u7075\u6d3b\u4f7f\u7528\u4f2a\u8868(SYSDUAL)<\/strong><\/li>\n<\/ol>\n<p>\u9996\u5148\uff0c\u53ef\u4ee5\u5229\u7528\u4f2a\u8868\u8fdb\u884c\u79d1\u5b66\u8ba1\u7b97\uff0c\u6267\u884c\u8bed\u53e5 SELECT 3*4 FROM SYSDUAL\uff0c\u5219\u53ef\u4ee5\u5f97\u5230\u7ed3\u679c 12\uff1b<\/p>\n<p>\u5176\u6b21\uff0c\u5728\u67d0\u4e9b\u65b9\u9762\u4f7f\u7528 SYSDUAL \u53ef\u63d0\u9ad8\u6548\u7387\u3002\u4f8b\u5982\uff1a\u67e5\u8be2\u8fc7\u7a0b\u4e2d\u8981\u5224\u65ad\u8868 t1 \u4e2d\u662f\u5426\u6709\u6ee1\u8db3 condition1 \u6761\u4ef6\u7684\u8bb0\u5f55\u5b58\u5728\uff0c\u53ef\u6267\u884c\u4ee5\u4e0b\u8bed\u53e5\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">  SELECT COUNT(*) INTO x FROM t1 WHERE condition1;\n<\/code><\/pre>\n<p>\u7136\u540e\uff0c\u6839\u636e\u53d8\u91cf x \u7684\u53d6\u503c\u6765\u5224\u65ad\u3002\u4f46\u662f\u5f53 t1 \u975e\u5e38\u5927\u65f6\u8be5\u8bed\u53e5\u6267\u884c\u901f\u5ea6\u5f88\u6162\uff0c\u800c\u4e14\u7531\u4e8e\u4e0d\u77e5\u9053 SELECT \u8fd4\u56de\u7684\u4e2a\u6570\uff0c\u4e0d\u80fd\u7528 SELECT *\u4ee3\u66ff\u3002\u4e8b\u5b9e\u4e0a\u8fd9\u4e2a\u67e5\u8be2\u53ef\u4ee5\u5229\u7528\u4f2a\u8868\u6765\u5b8c\u6210\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">  SELECT 'A' INTO y FROM SYSDUAL  WHERE EXISTS (SELECT 1 FROM t1 WHERE condition1);\n<\/code><\/pre>\n<p>\u5224\u65ad y \u503c\uff0c\u5982\u7b49\u4e8e'A'\u5219 T1 \u4e2d\u6709\u8bb0\u5f55\u3002\u8c03\u6574\u540e\u7684\u8bed\u53e5\u6267\u884c\u901f\u5ea6\u660e\u663e\u6bd4\u4e0a\u4e00\u53e5\u9ad8\u3002<\/p>\n<p>\u53e6\u5916\uff0c\u5728 DM \u7684\u8bed\u6cd5\u91cc\u662f\u53ef\u4ee5\u7701\u7565 FROM \u5b50\u53e5\u7684\uff0c\u8fd9\u65f6\u7cfb\u7edf\u4f1a\u81ea\u52a8\u52a0\u4e0a FROM SYSDUAL\u3002\u56e0\u6b64\u524d\u9762\u7684\u79d1\u5b66\u8ba1\u7b97\u4f8b\u5b50\u53ef\u4ee5\u7b80\u5316\u4e3a SELECT 3*4;<\/p>\n<ol start=\"4\">\n<li><strong>SELECT \u9879\u907f\u514d\u2018*\u2019<\/strong><\/li>\n<\/ol>\n<p>\u9664\u975e\u7528\u6237\u786e\u5b9e\u8981\u9009\u62e9\u8868\u4e2d\u6240\u6709\u5217\uff0c\u5426\u5219 SELECT *\u8fd9\u79cd\u5199\u6cd5\u5c06\u8ba9\u6267\u884c\u5668\u80cc\u4e0a\u6c89\u91cd\u7684\u8d1f\u8377\u3002\u56e0\u4e3a\u6bcf\u4e00\u5217\u7684\u6570\u636e\u4e0d\u5f97\u4e0d\u81ea\u4e0b\u5f80\u4e0a\u5c42\u5c42\u5411\u4e0a\u4f20\u9012\u3002\u4e0d\u4ec5\u4ec5\u5982\u6b64\uff0c\u5982\u679c\u7528\u6237\u67e5\u8be2\u7684\u662f\u5217\u5b58\u50a8\u8868\uff0c\u90a3\u4e48\u5217\u5b58\u50a8\u6240\u5e26\u6765\u7684 IO \u4f18\u52bf\u5c06\u635f\u8017\u6b86\u5c3d\u3002<\/p>\n<p>\u4efb\u4f55\u65f6\u5019\uff0c\u7528\u6237\u90fd\u8981\u4e86\u89e3\u8868\u7ed3\u6784\u548c\u4e1a\u52a1\u9700\u6c42\uff0c\u5c0f\u5fc3\u5730\u9009\u62e9\u9700\u8981\u7684\u5217\u5e76\u4e00\u4e00\u7ed9\u51fa\u540d\u79f0\uff0c\u907f\u514d\u76f4\u63a5\u7528 SELECT *\u3002<\/p>\n<ol start=\"5\">\n<li><strong>\u907f\u514d\u529f\u80fd\u76f8\u4f3c\u7684\u91cd\u590d\u7d22\u5f15<\/strong><\/li>\n<\/ol>\n<p>\u7d22\u5f15\u5e76\u975e\u8d8a\u591a\u8d8a\u597d\u3002\u629b\u5f00\u4f18\u5316\u5668\u9762\u5bf9\u4f17\u591a\u7d22\u5f15\u9010\u4e00\u8bd5\u63a2\u6240\u8017\u8d39\u7684\u65f6\u95f4\u4e0d\u8c08\uff0c\u5982\u679c\u8868\u4e0a\u589e\u5220\u6539\u64cd\u4f5c\u9891\u7e41\uff0c\u90a3\u4e48\u7d22\u5f15\u7684\u7ef4\u62a4\u5c06\u4f1a\u6210\u4e3a\u5927\u9ebb\u70e6\uff0c\u5c24\u5176\u662f\u51fd\u6570\u7d22\u5f15\u7684\u8ba1\u7b97\u5f00\u9500\u66f4\u4e0d\u80fd\u5ffd\u7565\u3002<\/p>\n<ol start=\"6\">\n<li><strong>\u4f7f\u7528 COUNT(*)\u7edf\u8ba1\u7ed3\u679c\u884c\u6570<\/strong><\/li>\n<\/ol>\n<p>\u5982\u679c\u5bf9\u5355\u8868\u67e5\u8be2 COUNT(*)\u4e14\u6ca1\u6709\u8fc7\u6ee4\u6761\u4ef6\uff0c\u90a3\u4e48 DM \u4f18\u5316\u5668\u4f1a\u76f4\u63a5\u8bfb\u53d6\u76f8\u5173\u7d22\u5f15\u4e2d\u5b58\u50a8\u7684\u884c\u6570\u4fe1\u606f\uff0c\u52a0\u4ee5\u56de\u6eda\u6bb5\u4e2d\u5176\u4ed6\u4e8b\u52a1\u63d2\u5165\u6216\u5220\u9664\u5143\u7ec4\u7684\u884c\u6570\u4fee\u6b63\uff0c\u8fc5\u901f\u5730\u7ed9\u51fa\u6700\u7ec8\u7ed3\u679c\u800c\u907f\u514d\u5bf9\u5b9e\u9645\u6570\u636e\u7684\u8bfb\u53d6\u3002\u76f8\u6bd4\u4e4b\u4e0b\uff0cCOUNT(\u5217\u540d)\u4f1a\u5bf9\u6570\u636e\u8fdb\u884c\u8bfb\u64cd\u4f5c\uff0c\u6267\u884c\u6548\u7387\u8fdc\u4f4e\u4e8e COUNT(*)\u3002<\/p>\n<p>\u5373\u4f7f\u67e5\u8be2\u4e2d\u542b\u6709\u8fc7\u6ee4\u6761\u4ef6\uff0c\u7531\u4e8e DM \u7279\u6709\u7684\u6279\u5904\u7406\u65b9\u5f0f\uff0cCOUNT(*)\u4f9d\u65e7\u5feb\u4e8e\u5176\u4ed6\u5199\u6cd5\u3002\u8fd9\u662f\u56e0\u4e3a COUNT(*)\u65e0\u9700\u53d6\u5f97\u884c\u7684\u5177\u4f53\u503c\u800c\u4ec5\u4ec5\u9700\u8981\u884c\u6570\u8fd9\u4e00\u4fe1\u606f\u3002<\/p>\n<p>\u9700\u8981\u989d\u5916\u8bf4\u660e\u7684\u662f\uff0cCOUNT(*)\u4f1a\u5c06 NULL \u503c\u8ba1\u7b97\u5728\u5185\u800c COUNT(\u5217\u540d)\u662f\u4e0d\u5305\u542b NULL \u503c\u7684\uff0c\u56e0\u6b64\u7528\u6237\u8981\u7ed3\u5408\u5e94\u7528\u573a\u666f\u51b3\u5b9a\u662f\u5426\u53ef\u4ee5\u4f7f\u7528 COUNT(*)\u3002<\/p>\n<ol start=\"7\">\n<li><strong>\u4f7f\u7528 EXPLAIN \u6765\u67e5\u770b\u6267\u884c\u8ba1\u5212<\/strong><\/li>\n<\/ol>\n<p>\u5728\u67e5\u8be2\u8bed\u53e5\u6216\u8005\u63d2\u5165\u3001\u5220\u9664\u3001\u66f4\u65b0\u8bed\u53e5\u524d\u589e\u52a0 EXPLAIN \u5173\u952e\u5b57\uff0cDM \u5c06\u663e\u793a\u5176\u6267\u884c\u8ba1\u5212\u800c\u65e0\u9700\u5b9e\u9645\u6267\u884c\u5b83\u3002\u67e5\u9605 V$SQL_NODE_NAME \u8868\u4e2d\u6bcf\u4e2a\u64cd\u4f5c\u7b26\u7684\u542b\u4e49\uff0c\u7528\u6237\u53ef\u4ee5\u5f88\u65b9\u4fbf\u4e14\u76f4\u89c2\u5730\u4e86\u89e3\u6570\u636e\u5982\u4f55\u88ab\u5904\u7406\u53ca\u4f20\u9012\u3002\u5982\u679c\u542f\u7528\u4e86\u7edf\u8ba1\u4fe1\u606f\u6536\u96c6\uff0c\u90a3\u4e48\u5bf9\u7167\u6267\u884c\u8ba1\u5212\u548c\u5bf9\u52a8\u6001\u89c6\u56fe v$sql_node_history\uff0cv$sql_node_name \u7684\u67e5\u8be2\u7ed3\u679c\uff0c\u7528\u6237\u5c31\u53ef\u4ee5\u77e5\u9053\u5728\u5b9e\u9645\u6267\u884c\u4e2d\u6bcf\u4e00\u4e2a\u64cd\u4f5c\u7b26\u6267\u884c\u7684\u65f6\u95f4\uff0c\u8fdb\u800c\u627e\u51fa\u6027\u80fd\u74f6\u9888\u3002<\/p>\n<ol start=\"8\">\n<li><strong>UNION \u548c UNION ALL \u7684\u9009\u62e9<\/strong><\/li>\n<\/ol>\n<p>UNION \u548c UNIONALL \u7684\u533a\u522b\u662f\u524d\u8005\u4f1a\u8fc7\u6ee4\u6389\u503c\u5b8c\u5168\u76f8\u540c\u7684\u5143\u7ec4\uff0c\u4e3a\u6b64 UNION \u64cd\u4f5c\u7b26\u9700\u8981\u5efa\u7acb HASH \u8868\u7f13\u5b58\u6240\u6709\u6570\u636e\u5e76\u53bb\u9664\u91cd\u590d\uff0c\u5f53 HASH \u8868\u5927\u5c0f\u8d85\u8fc7\u4e86 ini \u53c2\u6570\u6307\u5b9a\u7684\u9650\u5236\u65f6\u8fd8\u4f1a\u505a\u5237\u76d8\u3002<\/p>\n<p>\u56e0\u6b64\u5982\u679c\u5e94\u7528\u573a\u666f\u5e76\u4e0d\u5173\u5fc3\u91cd\u590d\u5143\u7ec4\u6216\u8005\u4e0d\u53ef\u80fd\u51fa\u73b0\u91cd\u590d\uff0c\u90a3\u4e48 UNION ALL \u65e0\u7591\u4f18\u4e8e UNION\u3002<\/p>\n<ol start=\"9\">\n<li><strong>\u4f18\u5316 GROUP BY ... HAVING<\/strong><\/li>\n<\/ol>\n<p>GROUP BY \u6700\u5e38\u89c1\u7684\u5b9e\u73b0\u6709 HASH \u5206\u7ec4\uff08HAGR\uff09\u548c\u6392\u5e8f\u5206\u7ec4\uff08SAGR\uff09\u3002\u524d\u8005\u9700\u8981\u7f13\u5b58\u4e2d\u95f4\u7ed3\u679c\uff1b\u5982\u679c\u7528\u6237\u5728 GROUP BY \u7684\u5217\u4e0a\u5efa\u7acb\u7d22\u5f15\uff0c\u90a3\u4e48\u4f18\u5316\u5668\u5c31\u4f1a\u5224\u65ad\u5e76\u53ef\u80fd\u4f7f\u7528\u4e0a\u8be5\u7d22\u5f15\uff0c\u8fd9\u65f6\u7684 GROUP BY \u5c31\u4f1a\u53d8\u4e3a SAGR\u3002<\/p>\n<p>HAVING \u662f\u5206\u7ec4\u540e\u5bf9\u7ed3\u679c\u96c6\u8fdb\u884c\u7684\u8fc7\u6ee4\uff0c\u5982\u679c\u8fc7\u6ee4\u6761\u4ef6\u65e0\u5173\u96c6\u51fd\u6570\u64cd\u4f5c\uff0c\u7528\u6237\u53ef\u4ee5\u8003\u8651\u5c06\u8fc7\u6ee4\u6761\u4ef6\u653e\u5728 WHERE \u800c\u4e0d\u662f HAVING \u4e2d\u3002DM \u4f18\u5316\u5668\u4f1a\u5224\u65ad\u5e76\u81ea\u52a8\u8f6c\u6362\u90e8\u5206\u7b49\u6548\u4e8e WHERE \u7684 HAVING \u5b50\u53e5\uff0c\u4f46\u663e\u5f0f\u5730\u7ed9\u51fa\u6700\u4f73 SQL \u8bed\u53e5\u4f1a\u8ba9\u4f18\u5316\u5668\u5de5\u4f5c\u5f97\u66f4\u597d\u3002<\/p>\n<ol start=\"10\">\n<li><strong>\u4f7f\u7528\u4f18\u5316\u5668\u63d0\u793a\uff08HINT\uff09<\/strong><\/li>\n<\/ol>\n<p>\u5229\u7528\u7ecf\u9a8c\u5bf9\u4f18\u5316\u5668\u7684\u8ba1\u5212\u9009\u62e9\u8fdb\u884c\u8c03\u6574\uff0cHINT \u662f SQL \u8c03\u6574\u4e0d\u53ef\u6216\u7f3a\u7684\u4e00\u6b65\u3002\u6211\u4eec\u5c06\u5728\u4e0b\u4e00\u8282\u7ed9\u51fa\u8be6\u7ec6\u8bf4\u660e\u3002<\/p>\n<h2 id=\"23-6-\u4f7f\u7528\u4f18\u5316\u5668\u63d0\u793a\" class=\"article-heading\" style=\"position: relative;\">23.6 \u4f7f\u7528\u4f18\u5316\u5668\u63d0\u793a<a class=\"article-anchor\" href=\"#23.6 \u4f7f\u7528\u4f18\u5316\u5668\u63d0\u793a\" aria-hidden=\"true\"><\/a><\/p>\n<div id=\"23.6 \u4f7f\u7528\u4f18\u5316\u5668\u63d0\u793a\" style=\"position: absolute; top: -100px;\"><\/div>\n<\/h2>\n<p>DM \u67e5\u8be2\u4f18\u5316\u5668\u91c7\u7528\u57fa\u4e8e\u4ee3\u4ef7\u7684\u65b9\u6cd5\u3002\u5728\u4f30\u8ba1\u4ee3\u4ef7\u65f6\uff0c\u4e3b\u8981\u4ee5\u7edf\u8ba1\u4fe1\u606f\u6216\u8005\u666e\u904d\u7684\u6570\u636e\u5206\u5e03\u4e3a\u4f9d\u636e\u3002\u5728\u5927\u591a\u6570\u60c5\u51b5\u4e0b\uff0c\u4f30\u8ba1\u7684\u4ee3\u4ef7\u90fd\u662f\u51c6\u786e\u7684\u3002\u4f46\u5728\u4e00\u4e9b\u6bd4\u8f83\u7279\u6b8a\u7684\u573a\u5408\uff0c\u4f8b\u5982\u7f3a\u5c11\u7edf\u8ba1\u4fe1\u606f\uff0c\u6216\u7edf\u8ba1\u4fe1\u606f\u9648\u65e7\uff0c\u6216\u62bd\u6837\u6570\u636e\u4e0d\u80fd\u5f88\u597d\u5730\u53cd\u6620\u6570\u636e\u5206\u5e03\u65f6\uff0c\u4f18\u5316\u5668\u9009\u62e9\u7684\u6267\u884c\u8ba1\u5212\u4e0d\u662f\u201c\u6700\u4f18\u201d\u7684\uff0c\u751a\u81f3\u53ef\u80fd\u662f\u5f88\u5dee\u7684\u6267\u884c\u8ba1\u5212\u3002<\/p>\n<p>DBA \u5bf9\u4e8e\u6570\u636e\u5206\u5e03\u662f\u5f88\u6e05\u695a\u7684\uff0c\u4ed6\u4eec\u77e5\u9053 SQL \u8bed\u53e5\u6309\u7167\u54ea\u79cd\u65b9\u6cd5\u6267\u884c\u4f1a\u6700\u5feb\u3002\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0cDBA \u53ef\u4ee5\u4e3b\u52a8\u8fdb\u884c\u4eba\u5de5\u5e72\u9884\uff0c\u6307\u793a\u4f18\u5316\u5668\u6309\u7167\u6307\u5b9a\u7684\u65b9\u6cd5\u53bb\u9009\u62e9 SQL \u7684\u6267\u884c\u8ba1\u5212\u3002<\/p>\n<p>DM \u628a\u8fd9\u79cd\u4eba\u5de5\u5e72\u9884\u4f18\u5316\u5668\u7684\u65b9\u6cd5\u79f0\u4e3a HINT\uff0c\u5b83\u4f7f\u4f18\u5316\u5668\u6839\u636e DBA \u7684 HINT \u63d0\u793a\u6765\u751f\u6210\u6307\u5b9a\u7684\u6267\u884c\u8ba1\u5212\u3002\u5982\u679c\u4f18\u5316\u5668\u65e0\u6cd5\u751f\u6210\u76f8\u5e94\u7684\u6267\u884c\u8ba1\u5212\uff0c\u8be5 HINT \u5c06\u4f1a\u88ab\u5ffd\u7565\u3002<\/p>\n<p>HINT \u7684\u5e38\u89c1\u683c\u5f0f\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">  SELECT \/*+ HINT1 [HINT2]*\/ \u5217\u540d FROM \u8868\u540d WHERE_CLAUSE ;\n  UPDATE \u8868\u540d \/*+ HINT1 [HINT2]*\/ SET \u5217\u540d =\u53d8\u91cf WHERE_CLAUSE ;\n  DELETE FROM \u8868\u540d \/*+ HINT1 [HINT2]*\/ WHERE_CLAUSE ;\n<\/code><\/pre>\n<p>\u9700\u8981\u6ce8\u610f\u7684\u662f\uff1a\u5982\u679c HINT \u7684\u8bed\u6cd5\u6ca1\u6709\u5199\u5bf9\u6216\u6307\u5b9a\u7684\u503c\u4e0d\u6b63\u786e\uff0cDM \u5e76\u4e0d\u4f1a\u62a5\u9519\uff0c\u800c\u662f\u76f4\u63a5\u5ffd\u7565 HINT \u7ee7\u7eed\u6267\u884c\u3002<\/p>\n<h3 id=\"23-6-1-INI\u53c2\u6570\u63d0\u793a\" class=\"article-heading\" style=\"position: relative;\">23.6.1 INI \u53c2\u6570\u63d0\u793a<a class=\"article-anchor\" href=\"#23.6.1 INI \u53c2\u6570\u63d0\u793a\" aria-hidden=\"true\"><\/a><\/p>\n<div id=\"23.6.1 INI \u53c2\u6570\u63d0\u793a\" style=\"position: absolute; top: -100px;\"><\/div>\n<\/h3>\n<p>DBA \u53ef\u4ee5\u901a\u8fc7 HINT \u65b9\u5f0f\u5bf9 INI \u53c2\u6570\u7684\u503c\u8fdb\u884c\u8bed\u53e5\u7ea7\u7684\u6307\u5b9a\u3002\u8bed\u53e5\u4e2d\u7684 HINT \u5bf9 INI \u53c2\u6570\u503c\u7684\u8bbe\u7f6e\u4f18\u5148\u7ea7\u9ad8\u4e8e INI \u6587\u4ef6\u4e2d\u53c2\u6570\u503c\u7684\u8bbe\u7f6e\u3002\u901a\u8fc7 HINT \u65b9\u5f0f\u53ea\u4f1a\u4fee\u6539 INI \u53c2\u6570\u7684\u5728\u672c\u4f1a\u8bdd\u4e2d\u7684\u503c\uff0c\u4e0d\u4f1a\u6539\u53d8\u5b83\u5728 INI \u6587\u4ef6\u4e2d\u7684\u503c\u3002<\/p>\n<p>\u652f\u6301\u4f7f\u7528 HINT \u7684 INI \u53c2\u6570\u53ef\u901a\u8fc7 V$HINT_INI_INFO \u52a8\u6001\u89c6\u56fe\u67e5\u8be2\u3002\u652f\u6301 HINT \u7684 INI \u53c2\u6570\u5206\u4e3a\u4e24\u7c7b\uff1a\u4e00\u662f HINT_TYPE \u4e3a\u201cOPT\u201d\uff0c\u8868\u793a\u5206\u6790\u9636\u6bb5\u4f7f\u7528\u7684\u53c2\u6570\uff1b\u4e8c\u662f HINT_TYPE \u4e3a\u201cEXEC\u201d\uff0c\u8868\u793a\u8fd0\u884c\u9636\u6bb5\u4f7f\u7528\u7684\u53c2\u6570\uff0c\u8fd0\u884c\u9636\u6bb5\u4f7f\u7528\u7684\u53c2\u6570\u5bf9\u4e8e\u89c6\u56fe\u65e0\u6548\u3002<\/p>\n<p>\u4f8b\u5982\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">  SELECT \/*+ENABLE_HASH_JOIN(1)*\/ * FROM T1,T2 WHERE C1=D1;\n<\/code><\/pre>\n<p>\u4e0a\u9762\u7684\u8bed\u53e5\u4e2d\u4f7f\u7528\u4e86 HINT\uff0c\u6307\u660e\u5728\u6267\u884c\u6b64 SQL \u65f6\u53c2\u6570 ENABLE_HASH_JOIN \u88ab\u7f6e\u4e3a 1\u3002<\/p>\n<h3 id=\"23-6-2-\u7d22\u5f15\u63d0\u793a\" class=\"article-heading\" style=\"position: relative;\">23.6.2 \u7d22\u5f15\u63d0\u793a<a class=\"article-anchor\" href=\"#23.6.2 \u7d22\u5f15\u63d0\u793a\" aria-hidden=\"true\"><\/a><\/p>\n<div id=\"23.6.2 \u7d22\u5f15\u63d0\u793a\" style=\"position: absolute; top: -100px;\"><\/div>\n<\/h3>\n<ol>\n<li><strong>\u4f7f\u7528\u7d22\u5f15<\/strong><\/li>\n<\/ol>\n<p>\u76ee\u524d DM \u63d0\u4f9b\u7684 HINT \u4e3a\u8868\u7d22\u5f15\u7684\u9009\u62e9 HINT\uff0c\u5b83\u6307\u793a\u4f7f\u7528\u6307\u5b9a\u7d22\u5f15\u8fdb\u884c\u6570\u636e\u68c0\u7d22\u3002<\/p>\n<p>\u8bed\u6cd5\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">\u8868\u540d + INDEX + \u7d22\u5f15\u540d\n\n\u6216\n\n\/*+ INDEX (\u8868\u540d[,] \u7d22\u5f15\u540d) {INDEX (\u8868\u540d[,] \u7d22\u5f15\u540d)} *\/\n<\/code><\/pre>\n<p>\u4e00\u4e2a\u8bed\u53e5\u4e2d\u6700\u591a\u6307\u5b9a 8 \u4e2a\u7d22\u5f15\u3002\u5728\u540e\u4e00\u79cd\u8bed\u6cd5\u683c\u5f0f\u4e2d\uff0c\u5982\u679c\u67e5\u8be2\u4e2d\u7ed9\u51fa\u4e86\u8868\u7684\u522b\u540d\u90a3\u4e48\u5fc5\u987b\u4f7f\u7528\u522b\u540d\u3002<\/p>\n<p>\u5047\u8bbe\u8868 t1 \u4e0a id \u548c name \u5217\u4e0a\u90fd\u5b58\u5728\u7740\u5355\u5217\u7d22\u5f15\u3002<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">    \/\/\u6570\u636e\u51c6\u5907\n    DROP TABLE T1 CASCADE;\n    CREATE TABLE T1 (ID INTEGER,NAME VARCHAR(128));\n    CREATE INDEX IDX_T1_ID ON T1(ID);\n    CREATE INDEX IDX_T1_NAME ON T1(NAME);\n<\/code><\/pre>\n<p>\u4f8b 1 \u5728\u67e5\u8be2\u8bed\u53e5\u4e2d\u6307\u5b9a\u7d22\u5f15\u3002<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">  SELECT * FROM t1 WHERE id &gt; 2011 AND name &lt; 'xxx';\n<\/code><\/pre>\n<p>\u5982\u679c id \u5217\u4e0a\u80fd\u8fc7\u6ee4\u66f4\u591a\u6570\u636e\uff0c\u5efa\u8bae\u6307\u793a\u7528\u7d22\u5f15 idx_t1_id\u3002<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">  SELECT * FROM t1 index idx_t1_id WHERE id &gt; 2011 AND name &lt; 'xxx';\n<\/code><\/pre>\n<p>\u6216<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">  SELECT \/*+INDEX(t1, idx_t1_id) *\/ * FROM t1 WHERE id &gt; 2011 AND name &lt; 'xxx';\n<\/code><\/pre>\n<p>\u4f8b 2 \u5f53\u6709\u591a\u4e2a\u7d22\u5f15\u65f6\uff0c\u8981\u6307\u5b9a\u4f7f\u6267\u884c\u8ba1\u5212\u6700\u4f18\u7684\u3002<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">  SELECT * FROM t1 WHERE id &gt; 2011 AND name &lt; 'xxx' ORDER BY name;\n<\/code><\/pre>\n<p>\u8003\u8651\u5230\u540e\u9762\u7684 name \u5217\u6392\u5e8f\u64cd\u4f5c\uff0c\u5efa\u8bae\u6307\u793a\u4f7f\u7528 name \u5217\u7684\u7d22\u5f15 idx_t1_name\uff0c\u56e0\u4e3a\u8fd9\u6837\u53ef\u4ee5\u5728\u6267\u884c\u8fc7\u7a0b\u4e2d\u7701\u7565\u6389\u6392\u5e8f\u64cd\u4f5c\uff08\u6267\u884c\u8ba1\u5212\u4e2d\u53ef\u4ee5\u770b\u51fa\u6765\uff09\uff0c\u6bd4\u4f7f\u7528 id \u5217\u7d22\u5f15\u4ee3\u4ef7\u5c0f\u3002<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">  SELECT * FROM t1 INDEX idx_t1_name WHERE id &gt; 2011 AND name &lt; 'xxx' ORDER BY name;\n<\/code><\/pre>\n<p>\u6216<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">  SELECT \/*+ INDEX(a idx_t1_name)*\/ * FROM t1 a WHERE id &gt; 2011 AND name &lt; 'xxx' ORDER BY name;\n<\/code><\/pre>\n<ol start=\"2\">\n<li><strong>\u4e0d\u4f7f\u7528\u7d22\u5f15<\/strong><\/li>\n<\/ol>\n<p>\u8bed\u6cd5\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">\/*+ NO_INDEX (\u8868\u540d[,] \u7d22\u5f15\u540d) { NO_INDEX (\u8868\u540d[,] \u7d22\u5f15\u540d)} *\/\n<\/code><\/pre>\n<p>\u53ef\u4ee5\u6307\u5b9a\u591a\u4e2a\u7d22\u5f15\uff0c\u5219\u8fd9\u4e9b\u7d22\u5f15\u90fd\u4e0d\u80fd\u88ab\u4f7f\u7528\u3002\u4e00\u4e2a\u8bed\u53e5\u4e2d\u6700\u591a\u6307\u5b9a 8 \u4e2a\u7d22\u5f15\u3002<\/p>\n<h3 id=\"23-6-3-\u8fde\u63a5\u65b9\u6cd5\u63d0\u793a\" class=\"article-heading\" style=\"position: relative;\">23.6.3 \u8fde\u63a5\u65b9\u6cd5\u63d0\u793a<a class=\"article-anchor\" href=\"#23.6.3 \u8fde\u63a5\u65b9\u6cd5\u63d0\u793a\" aria-hidden=\"true\"><\/a><\/p>\n<div id=\"23.6.3 \u8fde\u63a5\u65b9\u6cd5\u63d0\u793a\" style=\"position: absolute; top: -100px;\"><\/div>\n<\/h3>\n<p>DBA \u53ef\u4ee5\u901a\u8fc7\u6307\u5b9a\u4e24\u4e2a\u8868\u95f4\u7684\u8fde\u63a5\u65b9\u6cd5\u6765\u68c0\u6d4b\u4e0d\u540c\u8fde\u63a5\u65b9\u5f0f\u7684\u67e5\u8be2\u6548\u7387\uff0c\u6307\u5b9a\u7684\u8fde\u63a5\u53ef\u80fd\u7531\u4e8e\u65e0\u6cd5\u5b9e\u73b0\u6216\u4ee3\u4ef7\u8fc7\u9ad8\u800c\u88ab\u5ffd\u7565\u3002\u5982\u679c\u8fde\u63a5\u65b9\u6cd5\u63d0\u793a\u4e2d\u7684\u8868\u540d(\u522b\u540d)\u6216\u7d22\u5f15\u540d\u65e0\u6548\u4e5f\u4f1a\u88ab\u81ea\u52a8\u5ffd\u7565\u3002<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">    \/\/\u6570\u636e\u51c6\u5907\n    DROP TABLE T1 CASCADE;\n    DROP TABLE T2 CASCADE;\n\n    CREATE TABLE T1 (ID INTEGER,NAME VARCHAR(128));\n    CREATE TABLE T2 (ID INTEGER,NAME VARCHAR(128));\n\n    begin\n    for i in 1..1000 loop\n    insert into T1 values(i,'dameng'||i);\n    insert into T2 values(i+500,'damengsh'||i);\n    end loop;\n    end;\n<\/code><\/pre>\n<ol>\n<li><strong>USE_HASH<\/strong><\/li>\n<\/ol>\n<p>\u5f3a\u5236\u4e24\u4e2a\u8868\u95f4\u4f7f\u7528\u6307\u5b9a\u987a\u5e8f\u7684\u54c8\u5e0c\u8fde\u63a5\uff0c\u4f8b\u5982\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">    EXPLAIN SELECT \/*+ USE_HASH(T1, T2) *\/ * FROM T1, T2 WHERE T1.id = T2.id;\n    1   ##NSET2: [1, 9820, 104]\n    2     ##PRJT2: [1, 9820, 104]; exp_num(4), is_atom(FALSE)\n    3       ##HASH2 INNER JOIN: [1, 9820, 104];  KEY_NUM(1);\n    4         ##CSCN2: [0, 1001, 52]; INDEX33555536(T1)\n    5         ##CSCN2: [0, 1001, 52]; INDEX33555539(T2)\n<\/code><\/pre>\n<ol start=\"2\">\n<li><strong>NO_USE_HASH<\/strong><\/li>\n<\/ol>\n<p>\u5f3a\u5236\u4e24\u4e2a\u8868\u95f4\u4e0d\u80fd\u4f7f\u7528\u6307\u5b9a\u987a\u5e8f\u7684\u54c8\u5e0c\u8fde\u63a5\uff0c\u4f8b\u5982\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">    EXPLAIN SELECT \/*+ NO_USE_HASH(T1, T2) *\/ * FROM T1, T2 WHERE T1.id = T2.id;\n    1   ##NSET2: [1, 9820, 104]\n    2     ##PRJT2: [1, 9820, 104]; exp_num(4), is_atom(FALSE)\n    3       ##HASH2 INNER JOIN: [1, 9820, 104];  KEY_NUM(1);\n    4         ##CSCN2: [0, 1001, 52]; INDEX33555539(T2)\n    5         ##CSCN2: [0, 1001, 52]; INDEX33555536(T1)\n<\/code><\/pre>\n<p>NO_USE_HASH(T1,T2)\u8868\u793a\u4e0d\u5141\u8bb8 T1 \u4f5c\u4e3a\u5de6\u8868\uff0cT2 \u4f5c\u4e3a\u53f3\u8868\u7684\u54c8\u5e0c\u8fde\u63a5\uff0c\u4f46 T1 \u4f5c\u4e3a\u53f3\u8868\u7684\u54c8\u5e0c\u8fde\u63a5\u8fd8\u662f\u5141\u8bb8\u7684\u3002<\/p>\n<ol start=\"3\">\n<li><strong>USE_NL<\/strong><\/li>\n<\/ol>\n<p>\u5f3a\u5236\u4e24\u4e2a\u8868\u95f4\u4f7f\u7528\u5d4c\u5957\u5faa\u73af\u8fde\u63a5\uff0c\u4f8b\u5982\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">    EXPLAIN SELECT \/*+ USE_NL(a, b) *\/ * FROM T1 a, T2 b WHERE a.ID = b.ID;\n    1   ##NSET2: [22482, 9820, 104]\n    2     ##PRJT2: [22482, 9820, 104]; exp_num(4), is_atom(FALSE)\n    3       ##SLCT2: [22482, 9820, 104]; A.ID = B.ID\n    4         ##NEST LOOP INNER JOIN2: [22482, 9820, 104];\n    5           ##CSCN2: [0, 1001, 52]; INDEX33555536(T1 as A)\n    6           ##CSCN2: [0, 1001, 52]; INDEX33555539(T2 as B)\n<\/code><\/pre>\n<ol start=\"4\">\n<li><strong>NO_USE_NL<\/strong><\/li>\n<\/ol>\n<p>\u5f3a\u5236\u4e24\u4e2a\u8868\u95f4\u4e0d\u80fd\u4f7f\u7528\u5d4c\u5957\u5faa\u73af\u8fde\u63a5\uff0c\u4f8b\u5982\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">    EXPLAIN SELECT \/*+ NO_USE_NL(a, b) *\/ * FROM T1 a, T2 b WHERE a.ID = b.ID;\n    1   ##NSET2: [1, 9820, 104]\n    2     ##PRJT2: [1, 9820, 104]; exp_num(4), is_atom(FALSE)\n    3       ##HASH2 INNER JOIN: [1, 9820, 104];  KEY_NUM(1);\n    4         ##CSCN2: [0, 1001, 52]; INDEX33555536(T1 as A)\n    5         ##CSCN2: [0, 1001, 52]; INDEX33555539(T2 as B)\n<\/code><\/pre>\n<ol start=\"5\">\n<li><strong>USE_NL_WITH_INDEX<\/strong><\/li>\n<\/ol>\n<p>\u5f53\u8fde\u63a5\u60c5\u51b5\u4e3a\u5de6\u8868 + \u53f3\u8868\u7d22\u5f15\u65f6\uff0c\u5f3a\u5236\u4e24\u4e2a\u8868\u95f4\u4f7f\u7528\u7d22\u5f15\u8fde\u63a5\uff0c\u4f8b\u5982\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">    \/\/\u6570\u636e\u51c6\u5907\n    CREATE INDEX IDX_T2_ID ON T2(ID);\n    \/\/\u6267\u884cEXPLAIN\n    EXPLAIN SELECT \/*+ USE_NL_WITH_INDEX(T1, IDX_T2_ID) *\/ * FROM T1, T2 WHERE T1.ID = T2.ID;\n    1   #NSET2: [6, 9800, 104]\n    2     #PRJT2: [6, 9800, 104]; exp_num(4), is_atom(FALSE)\n    3       #NEST LOOP INDEX JOIN2: [6, 9800, 104]\n    4         #CSCN2: [0, 1000, 52]; INDEX33555536(T1)\n    5         #BLKUP2: [6, 3, 0]; IDX_T2_ID(T2)\n    6           #SSEK2: [6, 3, 0]; scan_type(ASC), IDX_T2_ID(T2), scan_range[T1.ID,T1.ID]\n<\/code><\/pre>\n<ol start=\"6\">\n<li>\n<p><strong>NO_USE_NL_WITH_INDEX<\/strong><\/p>\n<p>\u5f53\u8fde\u63a5\u60c5\u51b5\u4e3a\u5de6\u8868 + \u53f3\u8868\u7d22\u5f15\u65f6\uff0c\u5f3a\u5236\u4e24\u4e2a\u8868\u95f4\u4e0d\u80fd\u4f7f\u7528\u7d22\u5f15\u8fde\u63a5\uff0c\u4f8b\u5982\uff1a<\/p>\n<\/li>\n<\/ol>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">EXPLAIN SELECT \/*+ NO_USE_NL_WITH_INDEX(T1, IDX_T2_ID) *\/ * FROM T1, T2 WHERE T1.ID = T2.ID;\n    1   #NSET2: [1, 9800, 104]\n    2     #PRJT2: [1, 9800, 104]; exp_num(4), is_atom(FALSE)\n    3       #HASH2 INNER JOIN: [1, 9800, 104];  KEY_NUM(1);\n    4         #CSCN2: [0, 1000, 52]; INDEX33555536(T1)\n    5         #CSCN2: [0, 1000, 52]; INDEX33555539(T2)\n    \/\/\u4f7f\u7528\u5b8c\u6bd5\uff0c\u8bf7\u5220\u9664\u7d22\u5f15\n    DROP INDEX IDX_T2_ID;\n<\/code><\/pre>\n<ol start=\"7\">\n<li><strong>USE_MERGE<\/strong><\/li>\n<\/ol>\n<p>\u5f3a\u5236\u4e24\u4e2a\u8868\u95f4\u4f7f\u7528\u5f52\u5e76\u8fde\u63a5\u3002\u5f52\u5e76\u8fde\u63a5\u6240\u7528\u7684\u4e24\u4e2a\u5217\u90fd\u5fc5\u987b\u662f\u7d22\u5f15\u5217\u3002\u4f8b\u5982\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">    \/\/\u6570\u636e\u51c6\u5907\n    CREATE INDEX IDX_T1_ID ON T1(ID);\n    CREATE INDEX IDX_T2_ID ON T2(ID);\n    STAT 100 ON T1(ID);\n    STAT 100 ON T2(ID);\n    \/\/\u6267\u884cEXPLAIN\nEXPLAIN SELECT \/*+ USE_MERGE(T1,T2) *\/ * FROM T1, T2 WHERE T1.ID = T2.ID AND T1.ID &lt; 1 AND T2.ID &lt; 1;\n    1   #NSET2: [0, 1, 104]\n    2     #PRJT2: [0, 1, 104]; exp_num(4), is_atom(FALSE)\n    3       #MERGE INNER JOIN3: [0, 1, 104];\n    4         #BLKUP2: [0, 1, 52]; IDX_T1_ID(T1)\n    5           #SSEK2: [0, 1, 52]; scan_type(ASC), IDX_T1_ID(T1), scan_range(null2,1)\n    6         #BLKUP2: [0, 1, 52]; IDX_T2_ID(T2)\n    7           #SSEK2: [0, 1, 52]; scan_type(ASC), IDX_T2_ID(T2), scan_range(null2,1)\n<\/code><\/pre>\n<p>\u5f53\u8fde\u63a5\u7c7b\u578b\u4e3a\u5916\u8fde\u63a5\u65f6\uff0c\u65e0\u6cd5\u4f7f\u7528\u5f52\u5e76\u8fde\u63a5\uff0c\u6b64\u65f6\u5373\u4f7f\u6307\u5b9a USE_MERGE\uff0c\u4e5f\u4e0d\u8d77\u4f5c\u7528\u3002<\/p>\n<ol start=\"8\">\n<li>\n<p><strong>NO_USE_MERGE<\/strong><\/p>\n<p>\u5f3a\u5236\u4e24\u4e2a\u8868\u95f4\u4e0d\u80fd\u4f7f\u7528\u5f52\u5e76\u8fde\u63a5\uff0c\u4f8b\u5982\uff1a<\/p>\n<\/li>\n<\/ol>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">    EXPLAIN SELECT \/*+ NO_USE_MERGE(T1,T2) *\/ * FROM T1, T2 WHERE T1.ID = T2.ID AND T1.ID &gt; 1 AND T2.ID &gt; 1;\n    1   #NSET2: [1, 24, 104]\n    2     #PRJT2: [1, 24, 104]; exp_num(4), is_atom(FALSE)\n    3       #HASH2 INNER JOIN: [1, 24, 104];  KEY_NUM(1); KEY(T1.ID=T2.ID) KEY_NULL_EQU(0)\n    4         #SLCT2: [1, 50, 52]; T1.ID &gt; 1\n    5           #CSCN2: [1, 1000, 52]; INDEX33555458(T1)\n    6         #SLCT2: [1, 50, 52]; T2.ID &gt; 1\n    7           #CSCN2: [1, 1000, 52]; INDEX33555459(T2)\n    \/\/\u4f7f\u7528\u5b8c\u6bd5\uff0c\u8bf7\u5220\u9664\u7d22\u5f15\n    DROP INDEX IDX_T1_ID;\n    DROP INDEX IDX_T2_ID;\n<\/code><\/pre>\n<ol start=\"9\">\n<li>\n<p><strong>SEMI_GEN_CROSS<\/strong><\/p>\n<p>\u4f18\u5148\u91c7\u7528\u534a\u8fde\u63a5\u8f6c\u6362\u4e3a\u7b49\u4ef7\u7684\u5185\u8fde\u63a5\uff0c\u4ec5 OPTIMIZER_MODE=1 \u6709\u6548\u3002\u4f8b\u5982\uff1a<\/p>\n<\/li>\n<\/ol>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">    EXPLAIN SELECT \/*+ SEMI_GEN_CROSS  OPTIMIZER_MODE(1) *\/ COUNT(*) FROM T1 A WHERE A.ID IN (SELECT B.ID FROM T1 B);\n    1   ##NSET2: [3, 1, 8]\n    2     ##PRJT2: [3, 1, 8]; exp_num(1), is_atom(FALSE)\n    3       ##AAGR2: [3, 1, 8]; grp_num(0), sfun_num(1)\n    4         ##HASH2 INNER JOIN: [2, 1000, 8];  KEY_NUM(1);\n    5           ##PRJT2: [1, 1000, 4]; exp_num(1), is_atom(FALSE)\n    6             ##DISTINCT: [1, 1000, 4]\n    7               ##CSCN2: [0, 1000, 4]; INDEX33555531(T1 as B)\n    8           ##CSCN2: [0, 1000, 4]; INDEX33555531(T1 as A)\n<\/code><\/pre>\n<ol start=\"10\">\n<li>\n<p><strong>NO_SEMI_GEN_CROSS<\/strong><\/p>\n<p>\u4e0d\u91c7\u7528\u534a\u8fde\u63a5\u8f6c\u6362\u4e3a\u7b49\u4ef7\u7684\u5185\u8fde\u63a5\uff0c\u4ec5 OPTIMIZER_MODE=1 \u6709\u6548\u3002\u4f8b\u5982\uff1a<\/p>\n<\/li>\n<\/ol>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">    EXPLAIN SELECT \/*+ NO_SEMI_GEN_CROSS  OPTIMIZER_MODE(1) *\/ COUNT(*) FROM T1 A WHERE A.ID IN (SELECT B.ID FROM T1 B);\n    1   ##NSET2: [2, 1, 4]\n    2     ##PRJT2: [2, 1, 4]; exp_num(1), is_atom(FALSE)\n    3       ##AAGR2: [2, 1, 4]; grp_num(0), sfun_num(1)\n    4         ##HASH LEFT SEMI JOIN2: [1, 1000, 4]; KEY_NUM(1);\n    5           ##CSCN2: [0, 1000, 4]; INDEX33555531(T1 as A)\n    6           ##CSCN2: [0, 1000, 4]; INDEX33555531(T1 as B)\n<\/code><\/pre>\n<ol start=\"11\">\n<li>\n<p><strong>USE_CVT_VAR<\/strong><\/p>\n<p>\u4f18\u5148\u91c7\u7528\u53d8\u91cf\u6539\u5199\u65b9\u5f0f\u5b9e\u73b0\u8fde\u63a5\uff0c\u9002\u5408\u9a71\u52a8\u8868\u6570\u636e\u91cf\u5c11\u800c\u53e6\u4e00\u4fa7\u8ba1\u5212\u8f83\u590d\u6742\u7684\u573a\u666f\uff0c\u4ec5 OPTIMIZER_MODE=1 \u6709\u6548\u3002\u4f8b\u5982\uff1a<\/p>\n<\/li>\n<\/ol>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">    EXPLAIN SELECT \/*+ USE_CVT_VAR OPTIMIZER_MODE(1) *\/ COUNT(*) FROM T1 A WHERE A.id = 1001 AND EXISTS (SELECT 1 FROM T1 B, T1 C WHERE B.id = C.id AND A.name= B.name);\n    1   ##NSET2: [1, 1, 60]\n    2     ##PRJT2: [1, 1, 60]; exp_num(1), is_atom(FALSE)\n    3       ##AAGR2: [1, 1, 60]; grp_num(0), sfun_num(1)\n    4         ##NEST LOOP SEMI JOIN2: [0, 1, 60];  join condition(A.NAME = B.NAME)[with var]\n    5           ##SLCT2: [0, 1, 60]; A.ID = 1001\n    6             ##CSCN2: [0, 1000, 60]; INDEX33555531(T1 as A)\n    7           ##HASH2 INNER JOIN: [1, 1, 56];  KEY_NUM(1);\n    8             ##SLCT2: [0, 1, 52]; B.NAME = var1\n    9               ##CSCN2: [0, 1000, 52]; INDEX33555531(T1 as B)\n    10            ##CSCN2: [0, 1000, 4]; INDEX33555531(T1 as C)\n<\/code><\/pre>\n<ol start=\"12\">\n<li>\n<p><strong>NO_USE_CVT_VAR<\/strong><\/p>\n<p>\u4e0d\u8003\u8651\u53d8\u91cf\u6539\u5199\u65b9\u5f0f\u5b9e\u73b0\u8fde\u63a5\uff0c\u4ec5 OPTIMIZER_MODE=1 \u6709\u6548\u3002\u4f8b\u5982\uff1a<\/p>\n<\/li>\n<\/ol>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">    EXPLAIN SELECT \/*+ NO_USE_CVT_VAR OPTIMIZER_MODE(1) *\/ COUNT(*) FROM  T1 A WHERE A.id = 1001 AND EXISTS (SELECT 1 FROM T1 B, T1 C WHERE B.id = C.id AND A.name= B.name);\n    1   ##NSET2: [3, 1, 60]\n    2     ##PRJT2: [3, 1, 60]; exp_num(1), is_atom(FALSE)\n    3       ##AAGR2: [3, 1, 60]; grp_num(0), sfun_num(1)\n    4         ##HASH LEFT SEMI JOIN2: [2, 1, 60]; KEY_NUM(1);\n    5           ##SLCT2: [0, 1, 60]; A.ID = 1001\n    6             ##CSCN2: [0, 1000, 60]; INDEX33555531(T1 as A)\n    7           ##HASH2 INNER JOIN: [1, 1000, 56];  KEY_NUM(1);\n    8             ##CSCN2: [0, 1000, 4]; INDEX33555531(T1 as C)\n    9             ##CSCN2: [0, 1000, 52]; INDEX33555531(T1 as B)\n<\/code><\/pre>\n<ol start=\"13\">\n<li>\n<p><strong>ENHANCED_MERGE_JOIN<\/strong><\/p>\n<p>\u4e00\u822c\u60c5\u51b5\u4e0b\uff0c\u5f52\u5e76\u8fde\u63a5\u9700\u8981\u5de6\u53f3\u5b69\u5b50\u7684\u6570\u636e\u6309\u7167\u8fde\u63a5\u5217\u6709\u5e8f\uff0c\u4f7f\u7528\u6b64\u4f18\u5316\u5668\u63d0\u793a\u65f6\uff0c\u4f18\u5316\u5668\u5c06\u8003\u8651\u901a\u8fc7\u63d2\u5165\u6392\u5e8f\u64cd\u4f5c\u7b26\u7684\u65b9\u5f0f\u5b9e\u73b0\u5f52\u5e76\u8fde\u63a5\uff0c\u4ec5 OPTIMIZER_MODE=1 \u6709\u6548\u3002\u4f8b\u5982\uff1a<\/p>\n<\/li>\n<\/ol>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">    EXPLAIN SELECT \/*+ stat(T1 1M) stat(T2 1M) *\/COUNT(*) FROM T1, T2 WHERE T1.NAME=T2.NAME AND T1.ID=T2.ID;\n        \/\/\u4e0d\u52a0hint\u65f6\u8ba1\u5212\uff0c\u4f7f\u7528\u4e86\u54c8\u5e0c\u8fde\u63a5\n    1   #NSET2: [442, 1, 104]\n    2     #PRJT2: [442, 1, 104]; exp_num(1), is_atom(FALSE)\n    3       #AAGR2: [442, 1, 104]; grp_num(0), sfun_num(1)\n    4         #HASH2 INNER JOIN: [442, 1000000000000, 104];  KEY_NUM(2);\n    5           #CSCN2: [115, 1000000, 52]; INDEX33762063(T1)\n    6           #CSCN2: [115, 1000000, 52]; INDEX33762064(T2)\n        \/\/\u52a0HINT\u540e\u8ba1\u5212\uff0c\u901a\u8fc7\u589e\u52a0\u6392\u5e8f\u4ee5\u4f7f\u7528\u4e86\u5f52\u5e76\u8fde\u63a5\n    1   #NSET2: [436, 1, 104]\n    2     #PRJT2: [436, 1, 104]; exp_num(1), is_atom(FALSE)\n    3       #AAGR2: [436, 1, 104]; grp_num(0), sfun_num(1)\n    4         #MERGE INNER JOIN3: [436, 1000000000000, 104];\n    5           #SORT3: [122, 1000000, 52]; key_num(2), is_distinct(FALSE), top_flag(0)\n    6             #CSCN2: [115, 1000000, 52]; INDEX33762063(T1)\n    7           #SORT3: [122, 1000000, 52]; key_num(2), is_distinct(FALSE), top_flag(0)\n    8             #CSCN2: [115, 1000000, 52]; INDEX33762064(T2)\n\n<\/code><\/pre>\n<h3 id=\"23-6-4-\u8fde\u63a5\u987a\u5e8f\u63d0\u793a\" class=\"article-heading\" style=\"position: relative;\">23.6.4 \u8fde\u63a5\u987a\u5e8f\u63d0\u793a<a class=\"article-anchor\" href=\"#23.6.4 \u8fde\u63a5\u987a\u5e8f\u63d0\u793a\" aria-hidden=\"true\"><\/a><\/p>\n<div id=\"23.6.4 \u8fde\u63a5\u987a\u5e8f\u63d0\u793a\" style=\"position: absolute; top: -100px;\"><\/div>\n<\/h3>\n<p>\u591a\u8868\u8fde\u63a5\u65f6\u4f18\u5316\u5668\u4f1a\u8003\u8651\u5404\u79cd\u53ef\u80fd\u7684\u6392\u5217\u7ec4\u5408\u987a\u5e8f\u3002\u4f7f\u7528 ORDER HINT \u6307\u5b9a\u8fde\u63a5\u987a\u5e8f\u63d0\u793a\u53ef\u4ee5\u7f29\u5c0f\u4f18\u5316\u5668\u8bd5\u63a2\u7684\u6392\u5217\u7a7a\u95f4\uff0c\u8fdb\u800c\u5f97\u5230\u63a5\u8fd1 DBA \u6240\u671f\u671b\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u5982\u679c\u8fde\u63a5\u987a\u5e8f\u548c\u8fde\u63a5\u65b9\u6cd5\u63d0\u793a\u540c\u65f6\u6307\u5b9a\u4e14\u4e8c\u8005\u95f4\u5b58\u5728\u81ea\u76f8\u77db\u76fe\uff0c\u4f18\u5316\u5668\u4f1a\u4ee5\u8fde\u63a5\u987a\u5e8f\u63d0\u793a\u4e3a\u51c6\u3002<\/p>\n<p>\u8bed\u6cd5<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">\/*+ ORDER (T1, T2 , T3, \u2026 tn ) *\/\n<\/code><\/pre>\n<p>\u672c\u8282\u4e2d\u7684\u4f8b\u5b50\u7528\u5230 4 \u4e2a\u8868 T1, T2 , T3, T4\u3002<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">   CREATE TABLE T1(C1 INT,C2 VARCHAR);\n   CREATE TABLE T2(D1 INT,D2 VARCHAR);\n   CREATE TABLE T3(E1 INT,E2 VARCHAR);\n   CREATE TABLE T4(F1 INT,F2 VARCHAR);\n<\/code><\/pre>\n<p>\u4f8b\u5982\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">  SELECT * FROM t1, T2 , T3, T4 WHERE \u2026\n<\/code><\/pre>\n<p>\u5982\u679c\u671f\u671b\u8868\u7684\u8fde\u63a5\u987a\u5e8f\u662f T1, T2, T3\uff0c\u90a3\u4e48\u53ef\u4ee5\u52a0\u5165\u8fd9\u6837\u7684\u63d0\u793a\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">  SELECT \/*+ ORDER(T1, T2, T3 )*\/* FROM T1, T2 , T3, T4 WHERE \u2026\n<\/code><\/pre>\n<p>\u5728\u6307\u5b9a\u4e0a\u8ff0\u8fde\u63a5\u987a\u5e8f\u540e\uff0cT4,T1,T2,T3 \u6216 T1,T2,T4,T3 \u4f1a\u88ab\u8003\u8651\uff1bT3,T1,T2 \u6216 T1,T3,T2 \u4e0d\u88ab\u8003\u8651\u3002<\/p>\n<p>\u8fde\u63a5\u987a\u5e8f\u4e5f\u53ef\u4ee5\u548c\u8fde\u63a5\u65b9\u6cd5\u540c\u65f6\u6307\u5b9a\u7528\u4e8e\u5f97\u5230\u66f4\u7279\u5b9a\u7684\u6267\u884c\u8ba1\u5212\u3002<\/p>\n<p>\u4f8b\u5982\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">  EXPLAIN SELECT \/*+ OPTIMIZER_MODE(1), ORDER(T1,T2,T3,T4) ,USE_HASH(T1,T2), USE_HASH(T2,T3), USE_HASH(T3,T4)*\/* FROM T1,T2,T3,T4 WHERE T1.c1=T2.d1 AND T2.d2 = T3.e2 AND T3.e1 = T4.f1;\n<\/code><\/pre>\n<p>\u6b64\u65f6\u7684\u6267\u884c\u8ba1\u5212\u5982\u4e0b\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">    1   ##NSET2: [2, 1, 208]\n    2     ##PRJT2: [2, 1, 208]; exp_num(8), is_atom(FALSE)\n    3       ##HASH2 INNER JOIN: [2, 1, 208];  KEY_NUM(1);\n    4         ##HASH2 INNER JOIN: [1, 1, 156];  KEY_NUM(1);\n    5           ##HASH2 INNER JOIN: [0, 1, 104];  KEY_NUM(1);\n    6             ##CSCN2: [0, 1, 52]; INDEX33555490(T1)\n    7             ##CSCN2: [0, 1, 52]; INDEX33555491(T2)\n    8           ##CSCN2: [0, 1, 52]; INDEX33555492(T3)\n    9         ##CSCN2: [0, 1, 52]; INDEX33555493(T4)\n<\/code><\/pre>\n<h3 id=\"23-6-5-\u7edf\u8ba1\u4fe1\u606f\u63d0\u793a\" class=\"article-heading\" style=\"position: relative;\">23.6.5 \u7edf\u8ba1\u4fe1\u606f\u63d0\u793a<a class=\"article-anchor\" href=\"#23.6.5 \u7edf\u8ba1\u4fe1\u606f\u63d0\u793a\" aria-hidden=\"true\"><\/a><\/p>\n<div id=\"23.6.5 \u7edf\u8ba1\u4fe1\u606f\u63d0\u793a\" style=\"position: absolute; top: -100px;\"><\/div>\n<\/h3>\n<p>\u4f18\u5316\u5668\u5728\u8ba1\u5212\u4f18\u5316\u9636\u6bb5\u4f1a\u81ea\u52a8\u83b7\u53d6\u57fa\u8868\u7684\u884c\u6570\u3002\u4f46\u662f\u4e00\u4e9b\u7279\u6b8a\u7c7b\u578b\u7684\u8868\u884c\u6570\u4f30\u7b97\u5e76\u4e0d\u51c6\u786e\uff0c\u6216\u8005 DBA \u5e0c\u671b\u4e86\u89e3\u8868\u5927\u5c0f\u5bf9\u8ba1\u5212\u5f71\u54cd\u7684\u65f6\u5019\uff0c\u9700\u8981\u624b\u52a8\u8bbe\u7f6e\u8868\u7684\u884c\u6570\u3002<\/p>\n<p>\u8bed\u6cd5\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">\/*+ STAT (\u8868\u540d, \u884c\u6570) *\/\n<\/code><\/pre>\n<p>\u7edf\u8ba1\u4fe1\u606f\u63d0\u793a\u53ea\u80fd\u9488\u5bf9\u57fa\u8868\u8bbe\u7f6e\uff0c\u89c6\u56fe\u548c\u6d3e\u751f\u8868\u7b49\u5bf9\u8c61\u8bbe\u7f6e\u65e0\u6548\u3002\u5982\u679c\u8868\u5bf9\u8c61\u5b58\u5728\u522b\u540d\u5219\u5fc5\u987b\u4f7f\u7528\u522b\u540d\u3002\u884c\u6570\u53ea\u80fd\u4f7f\u7528\u6574\u6570\uff0c\u6216\u8005\u6574\u6570 +K\uff08\u5343\uff09\uff0c\u6574\u6570 +M\uff08\u767e\u4e07\uff09\uff0c\u6574\u6570 +G\uff08\u5341\u4ebf\uff09\u3002\u884c\u6570\u63d0\u793a\u8bbe\u7f6e\u540e\uff0c\u7edf\u8ba1\u4fe1\u606f\u7684\u5176\u5b83\u5185\u5bb9\u4e5f\u4f1a\u505a\u76f8\u5e94\u7684\u8c03\u6574\u3002<\/p>\n<p>\u4f8b\u5982\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">CREATE TABLE T_S(C1 INT);\nINSERT INTO T_S SELECT LEVEL FROM DUAL CONNECT BY LEVEL&lt;= 100;\nCOMMIT;\nSTAT 100 ON T_S(C1);\nEXPLAIN SELECT \/*+ STAT(T_S,1M) *\/ * FROM T_S WHERE C1 &lt;= 10;\n<\/code><\/pre>\n<p>\u8ba1\u5212\u5982\u4e0b\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">1   #NSET2: [117, 100000, 16]\n2     #PRJT2: [117, 100000, 16]; exp_num(2), is_atom(FALSE)\n3       #SLCT2: [117, 100000, 16]; T_S.C1 &lt;= 10\n4         #CSCN2: [117, 1000000, 16]; INDEX33555897(T_S)\n<\/code><\/pre>\n<p>\u4e0d\u4f7f\u7528 HINT \u65f6\u8ba1\u5212\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">1   #NSET2: [0, 10, 16]\n2     #PRJT2: [0, 10, 16]; exp_num(2), is_atom(FALSE)\n3       #SLCT2: [0, 10, 16]; T_S.C1 &lt;= 10\n4         #CSCN2: [0, 100, 16]; INDEX33555897(T_S)\n<\/code><\/pre>\n<h3 id=\"23-6-6-MPP\u672c\u5730\u5bf9\u8c61\u63d0\u793a\" class=\"article-heading\" style=\"position: relative;\">23.6.6 MPP \u672c\u5730\u5bf9\u8c61\u63d0\u793a<a class=\"article-anchor\" href=\"#23.6.6 MPP \u672c\u5730\u5bf9\u8c61\u63d0\u793a\" aria-hidden=\"true\"><\/a><\/p>\n<div id=\"23.6.6 MPP \u672c\u5730\u5bf9\u8c61\u63d0\u793a\" style=\"position: absolute; top: -100px;\"><\/div>\n<\/h3>\n<p>MPP \u73af\u5883\u4e0b\uff0c\u63d0\u4f9b\u4e00\u79cd\u5c06\u7528\u6237\u8868\u6216\u52a8\u6001\u89c6\u56fe\u4f5c\u4e3a\u672c\u5730\u5bf9\u8c61\u5904\u7406\u7684\u65b9\u6cd5\uff0c\u901a\u8fc7\u6307\u793a\u7b26 LOCAL_OBJECT(\u5bf9\u8c61\u540d\/\u522b\u540d) \u8fdb\u884c\u5904\u7406\u3002<\/p>\n<p>\u8bed\u6cd5\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">\/*+ LOCAL_OBJECT(\u5bf9\u8c61\u540d\/\u522b\u540d) *\/\n<\/code><\/pre>\n<p>\u5bf9\u4e8e\u7cfb\u7edf\u8868\u5f53\u505a\u672c\u5730\u5bf9\u8c61\u7684\u5904\u7406\uff0c\u672c\u65b9\u6cd5\u4e0d\u9002\u7528\uff0c\u7cfb\u7edf\u8868\u53ea\u80fd\u5728\u4e3b\u7ad9\u70b9\u624d\u80fd\u505a\u672c\u5730\u5bf9\u8c61\u5904\u7406\u3002<\/p>\n<p>\u4f8b MPP \u73af\u5883\u4e0b\uff0c\u6267\u884c\u4e0b\u9762\u6d4b\u4f8b\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">drop table t1;\n\ncreate table t1(c1 int) distributed by(c1);\n\ninsert into t1 values(0);\n\ninsert into t1 values(1);\n\ncommit;\n<\/code><\/pre>\n<p>\u5c06\u8868 t1 \u4f5c\u4e3a\u672c\u5730\u5bf9\u8c61\u8fdb\u884c\u5904\u7406\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">select \/*+local_object(t1)*\/ * from t1;\n<\/code><\/pre>\n<p>\u5c06\u8868 t1 \u4f5c\u4e3a\u672c\u5730\u5bf9\u8c61\u8fdb\u884c\u5904\u7406\uff0c\u652f\u6301\u4f7f\u7528 t1 \u7684\u522b\u540d X\u3002<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">select \/*+local_object(x)*\/ * from t1 x;\n<\/code><\/pre>\n<h3 id=\"23-6-7-\u5ffd\u7565\u91cd\u590d\u952e\u503c\u63d0\u793a\" class=\"article-heading\" style=\"position: relative;\">23.6.7 \u5ffd\u7565\u91cd\u590d\u952e\u503c\u63d0\u793a<a class=\"article-anchor\" href=\"#23.6.7 \u5ffd\u7565\u91cd\u590d\u952e\u503c\u63d0\u793a\" aria-hidden=\"true\"><\/a><\/p>\n<div id=\"23.6.7 \u5ffd\u7565\u91cd\u590d\u952e\u503c\u63d0\u793a\" style=\"position: absolute; top: -100px;\"><\/div>\n<\/h3>\n<p>\u5f53\u6267\u884c INSERT \u64cd\u4f5c\u65f6\uff0c\u5982\u679c\u5b58\u5728 UNIQUE \u7d22\u5f15\uff0c\u90a3\u4e48\u53d1\u751f\u4e86\u91cd\u590d\u952e\u503c\u51b2\u7a81\u3002\u4f7f\u7528 HINT IGNORE_ROW_ON_DUPKEY_INDEX \u5219\u53ef\u4ee5\u5ffd\u7565\u8be5\u51b2\u7a81\uff0c\u51b2\u7a81\u6570\u636e\u65e2\u4e0d\u8fdb\u884c\u63d2\u5165\u4e5f\u4e0d\u4f1a\u62a5\u9519\uff0c\u5176\u4ed6\u975e\u51b2\u7a81\u63d2\u5165\u6b63\u5e38\u8fdb\u884c\u3002<\/p>\n<p>\u6bcf\u4e00\u4e2a\u8be5 HINT \u4ec5\u5bf9\u5e94\u4e00\u4e2a\u7d22\u5f15\uff0c\u5982\u9700\u5ffd\u7565\u591a\u4e2a\u7d22\u5f15\u4e0a\u7684\u91cd\u590d\u952e\u503c\u51b2\u7a81\uff0c\u8bf7\u6307\u5b9a\u591a\u4e2a HINT\u3002<\/p>\n<p>\u8bed\u6cd5\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">\/*+IGNORE_ROW_ON_DUPKEY_INDEX(&lt;\u8868\u540d&gt; [(&lt;\u5217\u540d&gt;{,&lt;\u5217\u540d&gt;})])*\/\n<\/code><\/pre>\n<p>\u82e5 INSERT \u7684\u76ee\u6807\u8868\u5177\u6709\u522b\u540d\uff0c\u5219\u53ea\u6709 &lt; \u8868\u540d &gt; \u4e0e\u522b\u540d\u4e00\u81f4\u65f6 HINT \u624d\u751f\u6548\u3002<\/p>\n<p>\u652f\u6301\u4f7f\u7528\u8be5 HINT \u65f6\u4e0d\u6307\u5b9a &lt; \u5217\u540d &gt;\uff0c\u6b64\u65f6\u5ffd\u7565\u8868\u4e0a\u9664\u51fd\u6570\u7d22\u5f15\u5916\u7684\u6240\u6709 UNIQUE \u7d22\u5f15\u7684\u62a5\u9519\u3002\u5f53\u6307\u5b9a &lt; \u5217\u540d &gt; \u65f6\uff0c\u8be5 HINT \u6307\u5b9a\u7684 &lt; \u5217\u540d &gt; \u5fc5\u987b\u662f\u67d0\u4e2a UNIQUE \u7d22\u5f15\u7684\u524d\u5bfc\u5217\u6216\u8005\u5168\u90e8\u5217\uff0c\u5426\u5219\u62a5\u9519\uff1b\u5f53\u4f5c\u4e3a\u524d\u5bfc\u5217\u65f6\uff0c\u4e0d\u80fd\u51fa\u73b0\u5176\u5b83\u4e5f\u5c06\u8fd9\u4e9b\u5217\u4f5c\u4e3a\u524d\u5bfc\u5217\u7684 UNIQUE \u7d22\u5f15\uff0c\u5426\u5219\u62a5\u9519\u3002<\/p>\n<p>\u6307\u5b9a\u8be5 HINT \u65f6\uff0c\u4e0d\u652f\u6301 insert \u64cd\u4f5c\u7684\u6279\u91cf\u4f18\u5316\u5904\u7406\u3002<\/p>\n<p>\u4f8b \u6307\u5b9a IGNORE_ROW_ON_DUPKEY_INDEX \u4e0d\u4f1a\u62a5\u9519\u3002<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">drop table t1;\ncreate table t1(c1 int, c2 int, c3 int, c4 int);\ncreate unique index t1i1 on t1(c1,c2,c3);\ninsert  into t1 values (1,2,1,1);\ninsert  into t1 values (1,2,1,1); \/\/\u62a5\u9519\ninsert  \/*+IGNORE_ROW_ON_DUPKEY_INDEX(t1(c1,c2,c3))*\/ into t1 values (1,2,1,1);  \/\/\u4e0d\u62a5\u9519\ninsert  \/*+IGNORE_ROW_ON_DUPKEY_INDEX(t1)*\/ into t1 values (1,2,1,1);  \/\/\u4e0d\u62a5\u9519\n<\/code><\/pre>\n<h3 id=\"23-6-8-\u7981\u7528\u8ba1\u5212\u7f13\u5b58\u63d0\u793a\" class=\"article-heading\" style=\"position: relative;\">23.6.8 \u7981\u7528\u8ba1\u5212\u7f13\u5b58\u63d0\u793a<a class=\"article-anchor\" href=\"#23.6.8 \u7981\u7528\u8ba1\u5212\u7f13\u5b58\u63d0\u793a\" aria-hidden=\"true\"><\/a><\/p>\n<div id=\"23.6.8 \u7981\u7528\u8ba1\u5212\u7f13\u5b58\u63d0\u793a\" style=\"position: absolute; top: -100px;\"><\/div>\n<\/h3>\n<p>\u4f7f\u7528 HINT PLAN_NO_CACHE \u7981\u7528\u8ba1\u5212\u7f13\u5b58\uff0c\u5f53\u524d\u8bed\u53e5\u7684\u6267\u884c\u8ba1\u5212\u5c06\u4e0d\u4f1a\u88ab\u7f13\u5b58\u3002<\/p>\n<p>\u8bed\u6cd5\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">\/*+PLAN_NO_CACHE*\/\n<\/code><\/pre>\n<p>\u4f8b \u4e0b\u9762\u4e09\u6761 SELECT \u8bed\u53e5\u4e2d\uff0c\u7b2c\u4e00\u6761 select \u6307\u5b9a\u4e86 PLAN_NO_CACHE\uff0c\u5b83\u7684\u6267\u884c\u8ba1\u5212\u751f\u6210\u540e\u5c06\u4e0d\u4f1a\u88ab\u7f13\u5b58\uff1b\u7b2c\u4e8c\u6761 select \u672a\u6307\u5b9a PLAN_NO_CACHE\uff0c\u6240\u4ee5\u5b83\u7684\u6267\u884c\u8ba1\u5212\u88ab\u7f13\u5b58\u4e86\uff1b\u7b2c\u4e09\u6761 select \u5c06\u4e0d\u9700\u8981\u91cd\u65b0\u751f\u6210\u6267\u884c\u8ba1\u5212\uff0c\u53ef\u91cd\u7528\u7f13\u5b58\u7684\u7b2c\u4e8c\u6761 select \u7684\u6267\u884c\u8ba1\u5212\u3002<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">drop table t1;\n\ncreate table t1(c1 int);\n\nselect \/*+PLAN_NO_CACHE*\/ * from t1;\n\nselect * from t1;\n\nselect * from t1;\n<\/code><\/pre>\n<h3 id=\"23-6-9---DMDPC\u6570\u636e\u5206\u53d1\u65b9\u5f0f\u63d0\u793a\" class=\"article-heading\" style=\"position: relative;\">23.6.9   DMDPC \u6570\u636e\u5206\u53d1\u65b9\u5f0f\u63d0\u793a<a class=\"article-anchor\" href=\"#23.6.9 DMDPC \u6570\u636e\u5206\u53d1\u65b9\u5f0f\u63d0\u793a\" aria-hidden=\"true\"><\/a><\/p>\n<div id=\"23.6.9 DMDPC \u6570\u636e\u5206\u53d1\u65b9\u5f0f\u63d0\u793a\" style=\"position: absolute; top: -100px;\"><\/div>\n<\/h3>\n<p>DMDPC \u73af\u5883\u4e0b\u63d0\u4f9b\u4e86\u4e00\u79cd\u4e13\u95e8\u9488\u5bf9\u6307\u5b9a\u7684\u8fde\u63a5\u3001\u5206\u7ec4\u3001\u6392\u5e8f\u3001\u53bb\u91cd\u548c\u5206\u6790\u51fd\u6570\u64cd\u4f5c\u7b26\u6570\u636e\u5206\u53d1\u65b9\u5f0f\u8fdb\u884c\u4eba\u5de5\u5e72\u9884\u7684\u4f18\u5316\u5668\u63d0\u793a\u3002\u8be5\u63d0\u793a\u88ab\u91c7\u7eb3\u7684\u524d\u63d0\u662f\u6307\u5b9a\u7684\u5206\u53d1\u8def\u5f84\u6709\u6548\uff0c\u56e0\u4e3a\u4ee3\u4ef7\u539f\u56e0\u6ca1\u6709\u88ab\u4f18\u5316\u5668\u9009\u4e2d\u3002<\/p>\n<p>\u8bed\u6cd5\uff1a<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">\/*+DPC(\u5206\u53d1\u65b9\u5f0f\u63a2\u6d4b\u5e8f\u53f7 \u5206\u53d1\u65b9\u5f0f\u5b57\u7b26\u4e32)*\/\n<\/code><\/pre>\n<p>\u5176\u4e2d\uff0c\u5206\u53d1\u65b9\u5f0f\u63a2\u6d4b\u5e8f\u53f7\u8bf7\u5728 10053 trace event \u751f\u6210\u7684 TRACE \u6587\u4ef6\u4e2d\u67e5\u770b\uff0c\u4ee5 nth_try \u6807\u793a\uff1b\u5206\u53d1\u65b9\u5f0f\u5b57\u7b26\u4e32\u8bf7\u53c2\u8003 <a href=\"#23.6.9.1%\u4e8c\u5143\u64cd\u4f5c\u7b26\">23.6.9.1 \u4e8c\u5143\u64cd\u4f5c\u7b26<\/a>\u548c <a href=\"#23.6.9.2%\u4e00\u5143\u64cd\u4f5c\u7b26\">23.6.9.2 \u4e00\u5143\u64cd\u4f5c\u7b26<\/a>\u3002<\/p>\n<p>\u4f8b \u5728 SQL \u8bed\u53e5\u4e2d\u4f7f\u7528 DMDPC \u6570\u636e\u5206\u53d1\u65b9\u5f0f\u63d0\u793a\u3002<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">select \/*+ DPC(1 x_merge) *\/ para_name from v$dm_ini order by para_name;\n<\/code><\/pre>\n<h4 id=\"23-6-9-1-\u4e8c\u5143\u64cd\u4f5c\u7b26\" class=\"article-heading\" style=\"position: relative;\">23.6.9.1 \u4e8c\u5143\u64cd\u4f5c\u7b26<a class=\"article-anchor\" href=\"#23.6.9.1 \u4e8c\u5143\u64cd\u4f5c\u7b26\" aria-hidden=\"true\"><\/a><\/p>\n<div id=\"23.6.9.1 \u4e8c\u5143\u64cd\u4f5c\u7b26\" style=\"position: absolute; top: -100px;\"><\/div>\n<\/h4>\n<p>\u5bf9\u4e8e\u8fde\u63a5\u548c\u96c6\u5408\u8fd0\u7b97\u4e8c\u5143\u64cd\u4f5c\u7b26\uff0c\u53ef\u4f9b\u9009\u62e9\u7684\u5206\u53d1\u65b9\u5f0f\u5b57\u7b26\u4e32\u53c2\u89c1\u4e0b\u8868\u3002<\/p>\n<p><center>\u886823.1 \u4e8c\u5143\u64cd\u4f5c\u7b26\u7684\u5206\u53d1\u65b9\u5f0f\u5b57\u7b26\u4e32<\/center><\/p>\n<table>\n<thead>\n<tr>\n<th><strong>\u5206\u53d1\u65b9\u5f0f\u5b57\u7b26\u4e32<\/strong><\/th>\n<th><strong>\u542b\u4e49<\/strong><\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>L_NO_R_NO<\/td>\n<td>\u4e8c\u5143\u64cd\u4f5c\u7b26\u4e24\u4fa7\u90fd\u4e0d\u6dfb\u52a0\u4efb\u4f55\u6570\u636e\u5206\u53d1\u64cd\u4f5c\u7b26<\/td>\n<\/tr>\n<tr>\n<td>L_BRO<\/td>\n<td>\u4e8c\u5143\u64cd\u4f5c\u7b26\u5de6\u4fa7\u589e\u52a0\u5e7f\u64ad\u64cd\u4f5c<\/td>\n<\/tr>\n<tr>\n<td>R_BRO<\/td>\n<td>\u4e8c\u5143\u64cd\u4f5c\u7b26\u53f3\u4fa7\u589e\u52a0\u5e7f\u64ad\u64cd\u4f5c<\/td>\n<\/tr>\n<tr>\n<td>L_DIS_R_DIS<\/td>\n<td>\u5206\u522b\u5bf9\u4e8c\u5143\u64cd\u4f5c\u7b26\u4e24\u4fa7\u6570\u636e\u8fdb\u884c\u5206\u53d1<\/td>\n<\/tr>\n<tr>\n<td>L_DIS<\/td>\n<td>\u5bf9\u4e8c\u5143\u64cd\u4f5c\u7b26\u5de6\u4fa7\u6570\u636e\u8fdb\u884c\u5206\u53d1<\/td>\n<\/tr>\n<tr>\n<td>R_DIS<\/td>\n<td>\u5bf9\u4e8c\u5143\u64cd\u4f5c\u7b26\u53f3\u4fa7\u6570\u636e\u8fdb\u884c\u5206\u53d1<\/td>\n<\/tr>\n<tr>\n<td>L_GAT_R_GAT<\/td>\n<td>\u4e8c\u5143\u64cd\u4f5c\u7b26\u4e24\u4fa7\u6570\u636e\u6c47\u603b\u5230\u4e00\u4e2a\u7ebf\u7a0b<\/td>\n<\/tr>\n<tr>\n<td>ONE_GAT_ONLY<\/td>\n<td>\u4e8c\u5143\u64cd\u4f5c\u7b26\u4e00\u4fa7\u4e3a\u6307\u4ee4\uff0c\u53e6\u4e00\u4fa7\u4e3a\u975e\u6307\u4ee4\u3002\u975e\u6307\u4ee4\u7684\u4e00\u4fa7\u5c06\u6570\u636e\u53d1\u9001\u5230\u4e00\u4e2a SP \u7ad9\u70b9\u6267\u884c<\/td>\n<\/tr>\n<tr>\n<td>ONE_PART_ONLY<\/td>\n<td>\u4e8c\u5143\u64cd\u4f5c\u7b26\u4e00\u4fa7\u4e3a\u666e\u901a\u8868\uff0c\u53e6\u4e00\u6d4b\u5c06\u6570\u636e\u53d1\u9001\u5230\u6b64\u666e\u901a\u8868\u6240\u5728\u7684\u7ad9\u70b9\u6267\u884c<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u4f8b \u4e0b\u9762\u4e00\u6bb5 trace \u7247\u6bb5\u5c55\u793a\u4e86\u91c7\u7528\u4f18\u5316\u5668\u63d0\u793a\u4e2d\u7684\u4e8c\u5143\u64cd\u4f5c\u7b26\u5206\u53d1\u65b9\u5f0f\u7684\u60c5\u51b5\u3002<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">\/\/\u8fde\u63a5\u7247\u6bb5\uff0c\u6b63\u5728\u8bd5\u63a2\u7b2c5\u4e2a\u9700\u8981\u5206\u53d1\u7684\u64cd\u4f5c\u7b26hash left semi join(anti)\u3002\n*** probe best distribute method for hash left semi join(anti)(000000005089E500), DPC motion nth_try[5], restricts[0x12], self cost 1.000000\n  left motion cost: broadcast = 0.000011, dis = 0.000011, gather = 0.000011\n  right motion cost: broadcast = 0.000023, dis = 0.000011, gather = 0.000011\n  &gt; try    R_BRO(404), cost 0.062523, n_parallel 2, n_sites 0, best*\n  &gt; try L_DIS_R_DIS(405), cost 0.062523, n_parallel 2, n_sites 0, best*\n  &gt; try L_GAT_R_GAT(408), cost 1.000023, n_parallel 1, n_sites 0\n<\/code><\/pre>\n<h4 id=\"23-6-9-2-\u4e00\u5143\u64cd\u4f5c\u7b26\" class=\"article-heading\" style=\"position: relative;\">23.6.9.2 \u4e00\u5143\u64cd\u4f5c\u7b26<a class=\"article-anchor\" href=\"#23.6.9.2 \u4e00\u5143\u64cd\u4f5c\u7b26\" aria-hidden=\"true\"><\/a><\/p>\n<div id=\"23.6.9.2 \u4e00\u5143\u64cd\u4f5c\u7b26\" style=\"position: absolute; top: -100px;\"><\/div>\n<\/h4>\n<p>\u5bf9\u4e8e\u5206\u7ec4\uff08group\uff09\u3001\u6392\u5e8f\uff08order\uff09\u3001\u53bb\u91cd\uff08distinct\uff09\u548c\u5206\u6790\u51fd\u6570\uff08analytic function\uff09\u4e00\u5143\u64cd\u4f5c\u7b26\uff0c\u53ef\u4f9b\u9009\u62e9\u7684\u5206\u53d1\u65b9\u5f0f\u5b57\u7b26\u4e32\u53c2\u89c1\u4e0b\u8868\u3002<\/p>\n<p>\u4e0b\u8868\u4e2d\u7684 X \u4ee3\u8868 group\u3001order\u3001distinct \u6216 analytic function\u3002\u4f8b\u5982\uff0c\u5f53\u6309\u7167 group \u8fdb\u884c\u5206\u53d1\u65f6\uff0cx \u5373\u8868\u793a group\u3002<\/p>\n<p><center>\u886823.2 \u4e00\u5143\u64cd\u4f5c\u7b26\u7684\u5206\u53d1\u65b9\u5f0f\u5b57\u7b26\u4e32<\/center><\/p>\n<table>\n<thead>\n<tr>\n<th><strong>\u5206\u53d1\u65b9\u5f0f\u5b57\u7b26\u4e32<\/strong><\/th>\n<th><strong>\u542b\u4e49<\/strong><\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>X<\/td>\n<td>\u76f4\u63a5\u8fdb\u884c X<\/td>\n<\/tr>\n<tr>\n<td>X_DIS_X<\/td>\n<td>\u672c\u5730\u5148 X\uff0c\u5728\u6570\u636e\u5206\u53d1\u540e\u8fdb\u884c\u4e8c\u6b21 X<\/td>\n<\/tr>\n<tr>\n<td>DIS_X<\/td>\n<td>\u6570\u636e\u5206\u53d1\u540e\u8fdb\u884c X<\/td>\n<\/tr>\n<tr>\n<td>DIS_SORT_X<\/td>\n<td>\u6570\u636e\u5206\u53d1\u540e\u5148\u8fdb\u884c\u6392\u5e8f\uff0c\u63a5\u4e0b\u6765\u6267\u884c X<\/td>\n<\/tr>\n<tr>\n<td>X_GAT_X<\/td>\n<td>\u672c\u5730\u5148 X\uff0c\u6570\u636e\u6c47\u603b\u5230\u4e00\u4e2a\u7ebf\u7a0b\u540e\u8fdb\u884c\u4e8c\u6b21 X<\/td>\n<\/tr>\n<tr>\n<td>GAT_X<\/td>\n<td>\u6570\u636e\u6c47\u603b\u5230\u4e00\u4e2a\u7ebf\u7a0b\u540e\u8fdb\u884c X<\/td>\n<\/tr>\n<tr>\n<td>GAT_SORT_X<\/td>\n<td>\u6570\u636e\u6c47\u603b\u5230\u4e00\u4e2a\u7ebf\u7a0b\u540e\u6392\u5e8f\uff0c\u63a5\u4e0b\u6765\u6267\u884c X<\/td>\n<\/tr>\n<tr>\n<td>X_MERGE<\/td>\n<td>\u6bcf\u4e2a\u7ebf\u7a0b\u5148\u5206\u522b\u6392\u5e8f\uff0c\u6c47\u603b\u540e\u7531\u6700\u7ec8\u7684\u7ebf\u7a0b\u8fdb\u884c\u5f52\u5e76\u6392\u5e8f<\/td>\n<\/tr>\n<tr>\n<td>DIS_X_GAT_X<\/td>\n<td>\u5bf9\u65e0\u5206\u7ec4\u9879\u4e14\u542b\u6709 DISTINCT \u7684\u96c6\u51fd\u6570\uff0c\u5148\u6309\u96c6\u51fd\u6570\u53c2\u6570\u8fdb\u884c\u6570\u636e\u5206\u53d1\uff0c\u7136\u540e\u518d\u5bf9\u5206\u53d1\u7684\u6570\u636e\u8fdb\u884c X_GAT_X\u3002\u4ec5\u5f53 INI \u53c2\u6570 GROUP_OPT_FLAG \u53d6\u503c\u5305\u542b 64 \u65f6\u8003\u8651\u8be5\u65b9\u5f0f<\/td>\n<\/tr>\n<tr>\n<td>DIST_DIS_X_GAT_X<\/td>\n<td>\u548c DIS_X_GAT_X \u7c7b\u4f3c\u3002\u533a\u522b\u4e3a\uff0c\u5728\u5bf9\u96c6\u51fd\u6570\u53c2\u6570\u8fdb\u884c\u6570\u636e\u5206\u53d1\u524d\u5148\u505a\u4e00\u6b21\u53bb\u91cd\u5904\u7406\u3002\u4ec5\u5f53 INI \u53c2\u6570 GROUP_OPT_FLAG \u53d6\u503c\u5305\u542b 64 \u65f6\u8003\u8651\u8be5\u65b9\u5f0f<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u4f8b \u4e0b\u9762\u4e00\u6bb5 trace \u5c55\u793a\u4e86\u91c7\u7528\u4f18\u5316\u5668\u63d0\u793a\u4e2d\u7684\u4e8c\u5143\u64cd\u4f5c\u7b26\u5206\u53d1\u65b9\u5f0f\u7684\u60c5\u51b5\u3002<\/p>\n<pre><a class=\"btn-copy\" data-clipboard-target=\"\" style=\"text-align: center; float: right; margin-left: -64px; width: 64px; color: rgb(148, 163, 234); cursor: pointer; text-decoration: none; font-size: 13px; font-family: inherit; padding: 0px 0.3rem; position: relative; background: rgb(244, 244, 244); z-index: 9;\"><span>Copy<\/span><\/a><code class=\"language-plaintext hljs\" style=\"background: rgb(244, 244, 244);\">\/\/\u5206\u7ec4group\u7247\u6bb5\uff0c\u6b63\u8981\u63a2\u6d4b\u7b2c2\u4e2a\u9700\u8981\u5206\u53d1\u7684group\u3002\n*** probe best distribute method for group(000000000070E1F8), DPC motion nth_try[2], restricts[0xd], self cost 1.000000\n  left motion cost: broadcast = 236.980132, dis = 236.980132, gather = 236.980132\n  self motion cost: broadcast = 0.000006, dis = 0.000006, gather = 0.000006\n  &gt; try      X(420), cost 1.100000, n_parallel 0, n_sites 0, best*\n  &gt; try   X_GAT_X(424), cost 3.000006, n_parallel 0, n_sites 0\n  &gt; try    GAT_X(425), cost 239.980132, n_parallel 0, n_sites 0\n\n\/\/\u6392\u5e8forder\u7247\u6bb5\uff0c\u6b63\u8981\u63a2\u6d4b\u7b2c7\u4e2a\u9700\u8981\u5206\u53d1\u7684order\u3002\n*** probe best distribute method for order(0000000050897128), DPC motion nth_try[7], restricts[0x45], self cost 1.000000\n  left motion cost: broadcast = 0.000011, dis = 0.000011, gather = 0.000011\n  self motion cost: broadcast = 0.000011, dis = 0.000011, gather = 0.000011\n  &gt; try      X(420), cost 1.100000, n_parallel 0, n_sites 0, best*\n  &gt; try    GAT_X(425), cost 3.000011, n_parallel 0, n_sites 0\n  &gt; try   X_MERGE(427), cost 12.000011, n_parallel 0, n_sites 0\n\n\/\/\u6392\u5e8f\u53bb\u91cddistinct\u7247\u6bb5\uff0c\u6b63\u8981\u63a2\u6d4b\u7b2c1\u4e2a\u9700\u8981\u5206\u53d1\u7684distinct\u3002\n*** probe best distribute method for distinct(00000000007112E8), DPC motion nth_try[1], restricts[0x1f], self cost 21.828696\n  left motion cost: broadcast = 3.638299, dis = 1.819149, gather = 1.819149\n  self motion cost: broadcast = 0.036383, dis = 0.018191, gather = 0.018191\n  &gt; try      X(420), not available\n  &gt; try   X_DIS_X(421), cost 114.344539, n_parallel 1, n_sites 1, best*\n  &gt; try    DIS_X(422), cost 2464.784487, n_parallel 1, n_sites 1\n  &gt; try   X_GAT_X(424), cost 14.150826, n_parallel 0, n_sites 0, best*\n  &gt; try    GAT_X(425), cost 26.647845, n_parallel 0, n_sites 0\n\n\/\/\u5206\u6790\u51fd\u6570analytic function\u7247\u6bb5\uff0c\u6b63\u8981\u63a2\u6d4b\u7b2c6\u4e2a\u9700\u8981\u5206\u53d1\u7684analytic function\u3002\n*** probe best distribute method for analytic function(0000000050899AC0), DPC motion nth_try[6], restricts[0x181], self cost 1.000000\n  left motion cost: broadcast = 0.000011, dis = 0.000011, gather = 0.000011\n  self motion cost: broadcast = 0.000011, dis = 0.000011, gather = 0.000011\n  &gt; try      X(420), not available\n  &gt; try DIS_SORT_X(423), cost 20.000112, n_parallel 1, n_sites 1, best*\n  &gt; try GAT_SORT_X(426), cost 4.000011, n_parallel 0, n_sites 0\n<\/code><\/pre>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>23.1 \u7b80\u4ecb SQL \u8c03\u4f18\u4f5c\u4e3a\u6570\u636e\u5e93\u6027\u80fd\u8c03\u4f18\u4e2d\u7684\u6700\u540e\u4e00\u4e2a\u73af\u8282\uff0c\u5bf9\u67e5\u8be2\u6027\u80fd\u4ea7\u751f\u7740\u76f4\u63a5\u7684\u5f71\u54cd\u3002\u5728\u8fdb\u884c\u6b63\u5f0f\u7684 SQL \u8c03\u4f18\u524d\uff0c\u7528\u6237\u9996\u5148\u8981\u5173\u6ce8\u4e0b\u5217\u51e0\u70b9\uff1a \u8fbe\u68a6\u6570\u636e\u5e93\u5b89\u88c5\u65f6\u7684\u914d\u7f6e\u53c2\u6570\u662f\u5426\u7b26\u5408\u5e94\u7528\u573a\u666f\u9700\u6c42\uff1b \u8fbe\u68a6\u6570\u636e\u5e93\u7684 INI \u914d\u7f6e\u6587\u4ef6\u4e2d\u5404\u9879\u53c2\u6570\u662f\u5426\u5df2\u7ecf\u5904\u4e8e\u6700\u4f18\u914d\u7f6e\uff1b \u5e94\u7528\u7cfb\u7edf\u4e2d\u6570\u636e\u5e93\u8bbe\u8ba1\u662f\u5426\u5408\u7406\u3002 \u672c\u7ae0\u5c06\u4ecb\u7ecd\u5b9a\u4f4d\u9ad8\u8d1f\u8f7d\u7684 SQL \u8bed\u53e5\u7684\u65b9\u6cd5\uff0c\u5229\u7528\u81ea\u52a8 SQL \u8c03\u6574\u529f\u80fd\u8fdb\u884c\u4f18\u5316\uff0c\u4ee5\u53ca\u5982\u4f55\u5f00\u53d1\u6709\u6548\u7684 SQL \u8bed\u53e5\u548c\u4f7f\u7528\u4f18\u5316\u5668\u63d0\u793a\u6765\u5f71\u54cd\u6267\u884c\u8ba1\u5212\u3002 23.2 \u8c03\u4f18\u76ee\u6807 SQL \u8c03\u4f18\u7684\u6574\u4f53\u76ee\u6807\u662f\u4f7f\u7528\u6700\u4f18\u7684\u6267\u884c\u8ba1\u5212\uff0c\u8fd9\u610f\u5473\u7740 IO \u4ee5\u53ca CPU \u4ee3\u4ef7\u6700\u5c0f\u3002\u5177\u4f53\u800c\u8a00\u8c03\u4f18\u4e3b\u8981\u5173\u6ce8\u4e0b\u5217\u65b9\u9762\uff1a \u8868\u626b\u63cf \u5982\u679c\u8ba1\u5212\u4e2d\u5bf9\u67d0\u5927\u8868\u4f7f\u7528\u4e86\u5168\u7d22\u5f15\u626b\u63cf\uff0c\u90a3\u4e48\u7528\u6237\u9700\u8981\u5173\u6ce8\u662f\u5426\u5b58\u5728\u7740\u8be5\u8868\u7684\u67d0\u4e2a\u67e5\u8be2\u6761\u4ef6\u4f7f\u5f97\u8fc7\u6ee4\u540e\u53ef\u4ee5\u6dd8\u6c70\u81f3\u5c11\u4e00\u534a\u7684\u6570\u636e\u91cf\u3002\u901a\u8fc7\u6dfb\u52a0\u76f8\u5e94\u7684\u7d22\u5f15\uff0c\u5168\u7d22\u5f15\u626b\u63cf\u53ef\u80fd\u88ab\u8f6c\u6362\u4e3a\u8303\u56f4\u626b\u63cf\u6216\u7b49\u503c\u67e5\u627e\u3002\u6dfb\u52a0\u7684\u4e8c\u7ea7\u7d22\u5f15\u53ef\u4ee5\u5305\u542b\u8be5\u8868\u4e0a\u6240\u6709\u88ab\u9009\u62e9\u9879\u4ee5\u907f\u514d BLKUP2 \u64cd\u4f5c\u7b26\u7684\u67e5\u627e\u64cd\u4f5c\u5e26\u6765\u7684\u7b2c\u4e8c\u6b21 IO 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\u6240\u8c13\u56f0\u96be\u7684\u6b63\u5219\u8868\u8fbe\u5f0f\u662f\u6307\u5f00\u5934\u548c\u7ed3\u5c3e\u90fd\u4e3a\u901a\u914d\u7b26\u7684\u6b63\u5219\u8868\u8fbe\u5f0f\uff0c\u5982&#8217;L%&#8217;\u3001&#8217;%L&#8217;\uff0c\u4f18\u5316\u5668\u6ca1\u529e\u6cd5\u7f29\u5c0f\u5b83\u4eec\u7684\u5339\u914d\u8303\u56f4\uff0c\u4e5f\u4e0d\u53ef\u80fd\u7528\u5230\u7d22\u5f15\u800c\u5fc5\u987b\u4f7f\u7528\u5168\u8868\u626b\u63cf\u3002\u56e0\u6b64\u8981\u5c3d\u53ef\u80fd\u907f\u514d\u8fd9\u6837\u7684\u6b63\u5219\u8868\u8fbe\u5f0f\u3002 \u5982\u679c\u4ec5\u4ec5\u662f\u5f00\u5934\u4e3a\u901a\u914d\u7b26\uff0c\u7528\u6237\u53ef\u4ee5\u5728\u5217 a \u4e0a\u5efa\u7acb REVERSE(a)\u8fd9\u6837\u4e00\u4e2a\u51fd\u6570\u7d22\u5f15\uff0c\u5229\u7528\u51fd\u6570\u7d22\u5f15\u53cd\u8f6c\u5f85\u5339\u914d\u9879\u4ece\u800c\u4f7f\u7528\u51fd\u6570\u7d22\u5f15\u8fdb\u884c\u8303\u56f4\u626b\u63cf\u3002 \u7075\u6d3b\u4f7f\u7528\u4f2a\u8868(SYSDUAL) 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