{"id":1146,"date":"2015-01-17T17:02:18","date_gmt":"2015-01-17T09:02:18","guid":{"rendered":"http:\/\/coderbee.net\/?p=1146"},"modified":"2015-01-21T23:38:34","modified_gmt":"2015-01-21T15:38:34","slug":"oracle-hint","status":"publish","type":"post","link":"https:\/\/coderbee.net\/index.php\/db\/20150117\/1146","title":{"rendered":"Oracle hint"},"content":{"rendered":"<p>\u516c\u53f8\u7684DBA\u8981\u6c42\u628a\u4ed6\u4eec\u56fa\u5316\u7684\u6267\u884c\u8ba1\u5212\u6539\u7528 Oracle hint \u6765\u5b9e\u73b0\uff0c\u6b63\u597d\u4e86\u89e3\u4e0b\u5e73\u65f6\u6ca1\u6ce8\u610f\u53bb\u7528\u7684 hint\u3002<\/p>\n<h3>\u4f18\u5316\u65b9\u5f0f<\/h3>\n<p>Oracle\u7684\u4f18\u5316\u5668\u6709\u4e24\u79cd\u4f18\u5316\u65b9\u5f0f:<\/p>\n<ul>\n<li>\n<p>\u57fa\u4e8e\u89c4\u5219\u7684\u4f18\u5316\u65b9\u5f0f(Rule-Based Optimization\uff0c\u7b80\u79f0\u4e3aRBO) \uff1a\u4f18\u5316\u5668\u5728\u5206\u6790 SQL \u8bed\u53e5\u65f6\uff0c\u6240\u9075\u5faa\u7684\u662f Oracle  \u5185\u90e8\u9884\u5b9a\u7684\u4e00\u4e9b\u89c4\u5219\u3002\u6bd4\u5982\u6211\u4eec\u5e38\u89c1\u7684\uff0c\u5f53\u4e00\u4e2a <code>where<\/code> \u5b50\u53e5\u4e2d\u7684\u4e00\u5217\u6709\u7d22\u5f15\u65f6\u53bb\u8d70\u7d22\u5f15\u3002<\/p>\n<\/li>\n<li>\n<p>\u57fa\u4e8e\u4ee3\u4ef7\u7684\u4f18\u5316\u65b9\u5f0f(Cost-Based Optimization\uff0c\u7b80\u79f0\u4e3aCBO) \uff1b\u5b83\u662f\u770b\u8bed\u53e5\u7684\u4ee3\u4ef7(Cost)\uff0c\u8fd9\u91cc\u7684\u4ee3\u4ef7\u4e3b\u8981\u6307Cpu\u548c\u5185\u5b58\u3002\u4f18\u5316\u5668\u5728\u5224\u65ad\u662f\u5426\u7528\u8fd9\u79cd\u65b9\u5f0f\u65f6,\u4e3b\u8981\u53c2\u7167\u7684\u662f\u8868\u53ca\u7d22\u5f15\u7684\u7edf\u8ba1\u4fe1\u606f\u3002\u7edf\u8ba1\u4fe1\u606f\u7ed9\u51fa\u8868\u7684\u5927\u5c0f\u3001\u6709\u5c11\u884c\u3001\u6bcf\u884c\u7684\u957f\u5ea6\u7b49\u4fe1\u606f\u3002\u8fd9\u4e9b\u7edf\u8ba1\u4fe1\u606f\u8d77\u521d\u5728\u5e93\u5185\u662f\u6ca1\u6709\u7684\uff0c\u662f\u505a analyze \u540e\u624d\u51fa\u73b0\u7684\uff0c\u5f88\u591a\u7684\u65f6\u4faf\u8fc7\u671f\u7edf\u8ba1\u4fe1\u606f\u4f1a\u4ee4\u4f18\u5316\u5668\u505a\u51fa\u4e00\u4e2a\u9519\u8bef\u7684\u6267\u884c\u8ba1\u5212,\u56e0\u4e9b\u5e94\u53ca\u65f6\u66f4\u65b0\u8fd9\u4e9b\u4fe1\u606f\u3002<\/p>\n<\/li>\n<\/ul>\n<p>hint \u4e5f\u4e0d\u4f8b\u5916\uff0c\u9664\u4e86 <code>\/*+ rule *\/<\/code> \u5176\u4ed6\u7684\u90fd\u662f CBO \u4f18\u5316\u65b9\u5f0f \u3002<\/p>\n<h3>\u4f18\u5316\u6a21\u5f0f<\/h3>\n<p>\u4f18\u5316\u6a21\u5f0f\u5305\u62ec <code>Rule\u3001Choose\u3001First rows\u3001All rows<\/code> \u56db\u79cd\u65b9\u5f0f\uff1a<\/p>\n<ul>\n<li>Rule\uff1a\u57fa\u4e8e\u89c4\u5219\u7684\u65b9\u5f0f\u3002<\/li>\n<li>Choolse\uff1a\u9ed8\u8ba4\u7684\u60c5\u51b5\u4e0b Oracle \u7528\u7684\u4fbf\u662f\u8fd9\u79cd\u65b9\u5f0f\u3002\u6307\u7684\u662f\u5f53\u4e00\u4e2a\u8868\u6216\u6216\u7d22\u5f15\u6709\u7edf\u8ba1\u4fe1\u606f\uff0c\u5219\u8d70 CBO \u7684\u65b9\u5f0f\uff0c\u5982\u679c\u8868\u6216\u7d22\u5f15\u6ca1\u7edf\u8ba1\u4fe1\u606f\uff0c\u8868\u53c8\u4e0d\u662f\u7279\u522b\u7684\u5c0f\uff0c\u800c\u4e14\u76f8\u5e94\u7684\u5217\u6709\u7d22\u5f15\u65f6\uff0c\u90a3\u4e48\u5c31\u8d70\u7d22\u5f15\uff0c\u8d70 RBO \u7684\u65b9\u5f0f\u3002<\/li>\n<li>First Rows\uff1a\u5b83\u4e0e Choose \u65b9\u5f0f\u662f\u7c7b\u4f3c\u7684\uff0c\u6240\u4e0d\u540c\u7684\u662f\u5f53\u4e00\u4e2a\u8868\u6709\u7edf\u8ba1\u4fe1\u606f\u65f6\uff0c\u5b83\u5c06\u662f\u4ee5\u6700\u5feb\u7684\u65b9\u5f0f\u8fd4\u56de\u67e5\u8be2\u7684\u6700\u5148\u7684\u51e0\u884c\uff0c\u4ece\u603b\u4f53\u4e0a\u51cf\u5c11\u4e86\u54cd\u5e94\u65f6\u95f4\u3002<\/li>\n<li>All Rows:\u4e5f\u5c31\u662f\u6211\u4eec\u6240\u8bf4\u7684 Cost \u7684\u65b9\u5f0f\uff0c\u5f53\u4e00\u4e2a\u8868\u6709\u7edf\u8ba1\u4fe1\u606f\u65f6\uff0c\u5b83\u5c06\u4ee5\u6700\u5feb\u7684\u65b9\u5f0f\u8fd4\u56de\u8868\u7684\u6240\u6709\u7684\u884c\uff0c\u4ece\u603b\u4f53\u4e0a\u63d0\u9ad8\u67e5\u8be2\u7684\u541e\u5410\u91cf\u3002\u6ca1\u6709\u7edf\u8ba1\u4fe1\u606f\u5219\u8d70 RBO \u7684\u65b9\u5f0f\u3002<\/li>\n<\/ul>\n<h3>hint<\/h3>\n<h3>hint \u8bed\u6cd5<\/h3>\n<p>\uff1a <code>{DELETE|INSERT|SELECT|UPDATE} \/*+ hint [text] [hint[text]]... *\/<\/code><br \/>\n\u591a\u4e2ahint\u4e4b\u95f4\u9700\u8981\u7528\u7a7a\u683c\u5206\u5f00\uff0c\u5982\u679c\u6ca1\u6709\u6307\u5b9a\u6b63\u786e\u7684hint\uff0coracle\u8bb2\u5ffd\u89c6\u8be5hint\uff0c\u6ca1\u6709\u4efb\u4f55\u9519\u8bef\u63d0\u793a\u3002<\/p>\n<p>\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528\u6ce8\u91ca(comment)\u6765\u4e3a\u4e00\u4e2a\u8bed\u53e5\u6dfb\u52a0 hints\uff0c\u4e00\u4e2a\u8bed\u53e5\u5757\u53ea\u80fd\u6709\u4e00\u4e2a\u6ce8\u91ca\uff0c\u800c\u4e14\u6ce8\u91ca\u53ea\u80fd\u653e\u5728 <code>SELECT<\/code>\uff0c<code>UPDATE<\/code> \u6216  <code>DELETE<\/code> \u5173\u952e\u5b57\u7684\u540e\u9762\u3002<\/p>\n<p><!--more--><\/p>\n<p>\u5bf9\u4e8e\u6240\u6709 OLTP \u6570\u636e\u5e93\uff0c\u5efa\u8bae\u4ec5\u4ec5\u662f\u4f7f\u7528 parallel hint\uff0c\u800c\u4e0d\u662f\u5728\u8868\u6216\u7cfb\u7edf\u7ea7\u522b\u5f00\u542f\u5e76\u884c\uff1a<code>alter table customer parallel degree 35;<\/code> &#8212; \u5bf9 OLTP \u4e0d\u63a8\u8350\u3002<\/p>\n<p>\u6240\u6709\u5168\u8868\u626b\u63cf\u7684\u8bed\u53e5\uff0c\u90fd\u53ef\u4ee5\u6dfb\u52a0 parallel hint \u6765\u83b7\u5f97\u5e76\u884c\u67e5\u8be2\u7684\u597d\u5904\uff1a<code>select \/*+ FULL(emp) PARALLEL(emp, 35) *\/ from emp;<\/code><\/p>\n<p>\u4e0a\u9762\u7684\u8bed\u53e5\uff1a<\/p>\n<ul>\n<li>\u6ce8\u610f<code>\/*+<\/code>, <code>*<\/code> \u4e0e <code>+<\/code> \u4e4b\u95f4\u4e0d\u80fd\u6709\u7a7a\u683c\uff0c\u8981\u8fde\u7740\u5199\uff1b<\/li>\n<li><code>FULL(emp)<\/code> \u8868\u793a\u5bf9\u8868 <code>emp<\/code> \u6267\u884c\u5168\u8868\u626b\u63cf\uff0c\u5982\u679c\u662f\u591a\u8868\u5173\u8054\u67e5\u8be2\uff0c\u5219\u6bcf\u4e2a\u8868\u5fc5\u987b\u5206\u5f00\u5199\uff1b<\/li>\n<li><code>emp<\/code> \u662f\u8868\u540d\uff0c\u5982\u679c\u4f7f\u7528\u4e86\u522b\u540d\uff0c\u5219\u5fc5\u987b\u7528\u522b\u540d\uff0c\u5982\u679c\u662f\u591a\u8868\u5173\u8054\u67e5\u8be2\uff0c\u5219\u6bcf\u4e2a\u8868\u5fc5\u987b\u5206\u5f00\u5199\uff1b<\/li>\n<li><code>PARALLEL(emp, 35)<\/code> \u63d0\u793a\u6570\u636e\u5e93\u5728\u8868 <code>emp<\/code> \u4e0a\u5f00\u542f <code>35<\/code> \u4e2a\u5e76\u884c\u7ebf\u7a0b\u6765\u6267\u884c\uff1b<\/li>\n<li>\u5e76\u884c\u5ea6\u53ef\u4ee5\u91c7\u7528\u9ed8\u8ba4\u503c\uff0c\u8ba9\u6570\u636e\u5e93\u53bb\u51b3\u5b9a\uff0c\u5982\uff1a<code>PARALLEL(employee_table, DEFAULT, DEFAULT)<\/code> \uff1b<\/li>\n<\/ul>\n<p>\u5e76\u884c\u6267\u884c\u539f\u7406\uff0c\u6765\u81ea <a href=\"http:\/\/www.dba-oracle.com\/t_parallel_hint.htm\">Oracle parallel hint tips<\/a>\uff1a<br \/>\n<img decoding=\"async\" src=\"\/\/coderbee.net\/wp-content\/uploads\/2015\/01\/ani_oracle_parallel_query.gif\" alt=\"ani_oracle_parallel_query\" \/><\/p>\n<p>\u5e76\u884c\u6267\u884c\u5bf9\u4e8e\u64cd\u4f5c\u5927\u91cf\u7684\u6570\u636e\u662f\u5f88\u6709\u5fc5\u8981\u7684\uff0c\u5bf9\u6bd4\u4e86 DBA \u7ed9\u51fa\u7684\u6267\u884c\u8ba1\u5212\u4e0e\u81ea\u5df1\u52a0\u4e86\u5e76\u884c hint \u4e4b\u540e\u7684\u6267\u884c\u8ba1\u5212\uff0c\u6ca1\u4ec0\u4e48\u533a\u522b\u3002<\/p>\n<h3>\u5e38\u7528 hint<\/h3>\n<p>\u6765\u81ea\uff1a<a href=\"http:\/\/jojo117.iteye.com\/blog\/584845\">Oracle\u4f18\u5316\u5168\u653b\u7565\u4e00\uff08Oracle SQL Hint\uff09<\/a> \u3002<\/p>\n<p>\u524d10\u4e2a\u6bd4\u8f83\u5e38\u7528, \u524d3\u4e2a\u6700\u5e38\u7528\uff08\u6ce8\uff1a\u4ecd\u7136\u662f\u7d22\u5f15\u3001\u9a71\u52a8\u8868\u3001\u5e76\u884c\uff09\u3002<\/p>\n<ol>\n<li>\n<p><code>\/*+ INDEX *\/<\/code> \u548c <code>\/*+ INDEX(TABLE INDEX1, index2) *\/<\/code> \u548c <code>\/*+ INDEX(tab1.col1 tab2.col2) *\/<\/code> \u548c <code>\/*+ NO_INDEX *\/<\/code> \u548c <code>\/*+ NO_INDEX(TABLE INDEX1, index2) *\/<\/code> \u8868\u660e\u5bf9\u8868\u9009\u62e9\u7d22\u5f15\u7684\u626b\u63cf\u65b9\u6cd5\u3002 \u7b2c\u4e00\u79cd\u4e0d\u6307\u5b9a\u7d22\u5f15\u540d\u662f\u8ba9 oracle \u5bf9\u8868\u4e2d\u53ef\u7528\u7d22\u5f15\u6bd4\u8f83\u5e76\u9009\u62e9\u67d0\u4e2a\u6700\u4f73\u7d22\u5f15\uff1b\u7b2c\u4e8c\u79cd\u662f\u6307\u5b9a\u7d22\u5f15\u540d\u4e14\u53ef\u6307\u5b9a\u591a\u4e2a\u7d22\u5f15\uff1b \u7b2c\u4e09\u79cd\u662f 10g \u5f00\u59cb\u6709\u7684\uff0c\u6307\u5b9a\u5217\u540d\uff0c\u4e14\u8868\u540d\u53ef\u4e0d\u7528\u522b\u540d\uff1b\u7b2c\u56db\u79cd\u5373\u5168\u8868\u626b\u63cf; \u7b2c\u4e94\u79cd\u8868\u793a\u7981\u7528\u67d0\u4e2a\u7d22\u5f15\uff0c\u7279\u522b\u9002\u5408\u4e8e\u51c6\u5907\u5220\u9664\u67d0\u4e2a\u7d22\u5f15\u524d\u7684\u8bc4\u4f30\u64cd\u4f5c\u3002\u5982\u679c\u540c\u65f6\u4f7f\u7528\u4e86 <code>INDEX<\/code> \u548c <code>NO_INDEX<\/code> \u5219\u4e24\u4e2a\u63d0\u793a\u90fd\u4f1a\u88ab\u5ffd\u7565\u6389\u3002<\/p>\n<\/li>\n<li>\n<p><code>\/*+ ORDERED *\/<\/code>\uff1a<code>FROM<\/code> \u5b50\u53e5\u4e2d\u9ed8\u8ba4\u6700\u540e\u4e00\u4e2a\u8868\u662f\u9a71\u52a8\u8868\uff0c<code>ORDERED<\/code> \u5c06 <code>from<\/code> \u5b50\u53e5\u4e2d\u7b2c\u4e00\u4e2a\u8868\u4f5c\u4e3a\u9a71\u52a8\u8868\u3002\u7279\u522b\u9002\u5408\u4e8e\u591a\u8868\u8fde\u63a5\u975e\u5e38\u6162\u65f6\u5c1d\u8bd5\u3002<\/p>\n<\/li>\n<li>\n<p><code>\/*+ PARALLEL(table1,DEGREE) *\/<\/code> \u548c <code>\/*+ NO_PARALLEL(table1) *\/<\/code>\uff1a\u8be5\u63d0\u793a\u4f1a\u5c06\u9700\u8981\u6267\u884c\u5168\u8868\u626b\u63cf\u7684\u67e5\u8be2\u5206\u6210\u591a\u4e2a\u90e8\u5206\uff08\u5e76\u884c\u5ea6\uff09\u6267\u884c, \u7136\u540e\u5728\u4e0d\u540c\u7684\u64cd\u4f5c\u7cfb\u7edf\u8fdb\u7a0b\u4e2d\u5904\u7406\u6bcf\u4e2a\u90e8\u5206\u3002\u8be5\u63d0\u793a\u8fd8\u53ef\u7528\u4e8eDML\u8bed\u53e5\u3002\u5982\u679c SQL \u91cc\u8fd8\u6709\u6392\u5e8f\u64cd\u4f5c\uff0c\u8fdb\u7a0b\u6570\u4f1a\u7ffb\u500d\uff0c\u6b64\u5916\u8fd8\u6709\u4e00\u4e2a\u4e00\u4e2a\u8d1f\u8d23\u7ec4\u5408\u8fd9\u4e9b\u90e8\u5206\u7684\u8fdb\u7a0b\u3002<code>NO_PARALLEL<\/code> \u662f\u7981\u6b62\u5e76\u884c\u64cd\u4f5c\u3002<\/p>\n<\/li>\n<li>\n<p><code>\/*+ FIRST_ROWS *\/<\/code> \u548c <code>\/*+ FIRST_ROWS(n) *\/<\/code>\uff1a\u8868\u793a\u7528\u6700\u5feb\u901f\u5ea6\u83b7\u5f97\u7b2c <code>1\/n<\/code> \u884c, \u83b7\u5f97\u6700\u4f73\u54cd\u5e94\u65f6\u95f4\uff0c\u4f7f\u8d44\u6e90\u6d88\u8017\u6700\u5c0f\u5316\u3002\u5728 <code>update<\/code> \u548c <code>delete<\/code> \u8bed\u53e5\u91cc\u4f1a\u88ab\u5ffd\u7565, \u4f7f\u7528\u5206\u7ec4\u8bed\u53e5\u5982 <code>group by\/distinct\/intersect\/minus\/union<\/code> \u65f6\u4e5f\u4f1a\u88ab\u5ffd\u7565\u3002<\/p>\n<\/li>\n<li>\n<p><code>\/*+ RULE *\/<\/code>\uff1a\u5bf9\u8bed\u53e5\u5757\u9009\u62e9\u57fa\u4e8e\u89c4\u5219\u7684\u4f18\u5316\u65b9\u6cd5\u3002<\/p>\n<\/li>\n<li>\n<p><code>\/*+ FULL(TABLE) *\/<\/code>\uff1a\u5bf9\u8868\u9009\u62e9\u5168\u5c40\u626b\u63cf\u7684\u65b9\u6cd5\u3002<\/p>\n<\/li>\n<li>\n<p><code>\/*+ LEADING(TABLE) *\/<\/code> \uff1a\u7c7b\u4f3c\u4e8e <code>ORDERED<\/code>\u63d0\u793a\uff0c\u5c06\u6307\u5b9a\u7684\u8868\u4f5c\u4e3a\u8fde\u63a5\u6b21\u5e8f\u4e2d\u7684\u9a71\u52a8\u8868\u3002<\/p>\n<\/li>\n<li>\n<p><code>\/*+ USE_NL(TABLE1,TABLE2) *\/<\/code>\uff1a\u5c06\u6307\u5b9a\u8868\u4e0e\u5d4c\u5957\u7684\u8fde\u63a5\u7684\u884c\u6e90\u8fdb\u884c\u8fde\u63a5\uff0c\u4ee5\u6700\u5feb\u901f\u5ea6\u8fd4\u56de\u7b2c\u4e00\u884c\u518d\u8fde\u63a5\uff0c\u4e0e <code>USE_MERGE<\/code> \u521a\u597d\u76f8\u53cd\u3002<\/p>\n<\/li>\n<li>\n<p><code>\/*+ APPEND *\/<\/code> \u548c <code>\/*+ NOAPPEND *\/<\/code>\uff1a\u76f4\u63a5\u63d2\u5165\u5230\u8868\u7684\u6700\u540e\uff0c\u8be5\u63d0\u793a\u4e0d\u4f1a\u68c0\u67e5\u5f53\u524d\u662f\u5426\u6709\u63d2\u5165\u64cd\u4f5c\u6240\u9700\u7684\u5757\u7a7a\u95f4\u800c\u662f\u76f4\u63a5\u6dfb\u52a0\u5230\u65b0\u5757\u4e2d\uff0c\u6240\u4ee5\u53ef\u4ee5\u63d0\u9ad8\u901f\u5ea6\u3002 \u5f53\u7136\u4e5f\u4f1a\u6d6a\u8d39\u4e9b\u7a7a\u95f4\uff0c\u56e0\u4e3a\u5b83\u4e0d\u4f1a\u4f7f\u7528\u90a3\u4e9b\u505a\u4e86 <code>delete<\/code> \u64cd\u4f5c\u7684\u5757\u7a7a\u95f4\u3002<code>NOAPPEND<\/code> \u63d0\u793a\u5219\u76f8\u53cd\uff0c\u6240\u4ee5\u4f1a\u53d6\u6d88 <code>PARALLEL<\/code> \u63d0\u793a\u7684\u9ed8\u8ba4 <code>APPEND<\/code> \u63d0\u793a\u3002<\/p>\n<\/li>\n<li>\n<p><code>\/*+ USE_HASH(TABLE1,table2) *\/<\/code>\uff1a\u5c06\u6307\u5b9a\u7684\u8868\u4e0e\u5176\u5b83\u884c\u6e90\u901a\u8fc7\u54c8\u5e0c\u8fde\u63a5\u65b9\u5f0f\u8fde\u63a5\u8d77\u6765\uff0c\u4e3a\u8f83\u5927\u7684\u7ed3\u679c\u96c6\u63d0\u4f9b\u6700\u4f73\u54cd\u5e94\u65f6\u95f4\u3002 \u7c7b\u4f3c\u4e8e\u5728\u8fde\u63a5\u8868\u7684\u7ed3\u679c\u4e2d\u904d\u5386\u6bcf\u4e2a\u8868\u4e0a\u6bcf\u4e2a\u7ed3\u679c\u7684\u5d4c\u5957\u5faa\u73af\uff0c\u6307\u5b9a\u7684hash\u8868\u5c06\u88ab\u653e\u5165\u5185\u5b58\uff0c\u6240\u4ee5\u9700\u8981\u6709\u8db3\u591f\u7684\u5185\u5b58\uff08<code>hash_area_size<\/code> \u6216 <code>pga_aggregate_target<\/code>\uff09\u624d\u80fd\u4fdd\u8bc1\u8bed\u53e5\u6b63\u786e\u6267\u884c\uff0c\u5426\u5219\u5c06\u5728\u78c1\u76d8\u91cc\u8fdb\u884c\u3002<\/p>\n<\/li>\n<li>\n<p><code>\/*+ USE_MERGE(TABLE) *\/<\/code>\uff1a\u5c06\u6307\u5b9a\u7684\u8868\u4e0e\u5176\u5b83\u884c\u6e90\u901a\u8fc7\u5408\u5e76\u6392\u5e8f\u8fde\u63a5\u65b9\u5f0f\u8fde\u63a5\u8d77\u6765\uff0c\u7279\u522b\u9002\u5408\u4e8e\u90a3\u79cd\u5728\u591a\u4e2a\u8868\u5927\u91cf\u884c\u4e0a\u8fdb\u884c\u96c6\u5408\u64cd\u4f5c\u7684\u67e5\u8be2\uff0c\u5b83\u4f1a\u5c06\u6307\u5b9a\u8868\u68c0\u7d22\u5230\u7684\u7684\u6240\u6709\u884c\u6392\u5e8f\u540e\u518d\u88ab\u5408\u5e76\uff0c\u4e0e <code>USE_NL<\/code> \u521a\u597d\u76f8\u53cd\u3002<\/p>\n<\/li>\n<li>\n<p><code>\/*+ ALL_ROWS *\/<\/code>\uff1a\u8868\u660e\u5bf9\u8bed\u53e5\u5757\u9009\u62e9\u57fa\u4e8e\u5f00\u9500\u7684\u4f18\u5316\u65b9\u6cd5\uff0c\u5e76\u83b7\u5f97\u6700\u4f73\u541e\u5410\u91cf\uff0c\u4f7f\u8d44\u6e90\u6d88\u8017\u6700\u5c0f\u5316\uff0c \u53ef\u80fd\u4f1a\u9650\u5236\u67d0\u4e9b\u7d22\u5f15\u7684\u4f7f\u7528\u3002<\/p>\n<\/li>\n<li>\n<p><code>\/*+ CLUSTER(TABLE) *\/<\/code>\uff1a\u63d0\u793a\u660e\u786e\u8868\u660e\u5bf9\u6307\u5b9a\u8868\u9009\u62e9\u7c07\u626b\u63cf\u7684\u8bbf\u95ee\u65b9\u6cd5\u3002\u5982\u679c\u7ecf\u5e38\u8bbf\u95ee\u8fde\u63a5\u8868\u4f46\u5f88\u5c11\u4fee\u6539\u5b83\uff0c\u90a3\u5c31\u4f7f\u7528\u96c6\u7fa4\u63d0\u793a\u3002<\/p>\n<\/li>\n<li>\n<p><code>\/*+ INDEX_ASC(TABLE INDEX1, INDEX2) *\/<\/code>\uff1a\u8868\u660e\u5bf9\u8868\u9009\u62e9\u7d22\u5f15\u5347\u5e8f\u7684\u626b\u63cf\u65b9\u6cd5\u3002\u4ece8i\u5f00\u59cb\uff0c\u8fd9\u4e2a\u63d0\u793a\u548c <code>INDEX<\/code> \u63d0\u793a\u529f\u80fd\u4e00\u6837\uff0c\u56e0\u4e3a\u9ed8\u8ba4 oracle \u5c31\u662f\u6309\u7167\u5347\u5e8f\u626b\u63cf\u7d22\u5f15\u7684\uff0c\u9664\u975e\u672a\u6765 oracle \u8fd8\u63a8\u51fa\u964d\u5e8f\u626b\u63cf\u7d22\u5f15\u3002<\/p>\n<\/li>\n<li>\n<p><code>\/*+ INDEX_COMBINE(TABLE INDEX1, INDEX2) *\/<\/code>\uff1a\u6307\u5b9a\u591a\u4e2a\u4f4d\u56fe\u7d22\u5f15\uff0c\u5bf9\u4e8eB\u6811\u7d22\u5f15\u5219\u4f7f\u7528 <code>INDEX<\/code> \u8fd9\u4e2a\u63d0\u793a\uff0c\u5982\u679c <code>INDEX_COMBINE<\/code> \u4e2d\u6ca1\u6709\u63d0\u4f9b\u4f5c\u4e3a\u53c2\u6570\u7684\u7d22\u5f15\uff0c\u5c06\u9009\u62e9\u51fa\u4f4d\u56fe\u7d22\u5f15\u7684\u5e03\u5c14\u7ec4\u5408\u65b9\u5f0f\u3002<\/p>\n<\/li>\n<li>\n<p><code>\/*+ INDEX_JOIN(TABLE INDEX1, INDEX2) *\/<\/code>\uff1a\u5408\u5e76\u7d22\u5f15\uff0c\u6240\u6709\u6570\u636e\u90fd\u5df2\u7ecf\u5305\u542b\u5728\u8fd9\u4e24\u4e2a\u7d22\u5f15\u91cc\uff0c\u4e0d\u4f1a\u518d\u53bb\u8bbf\u95ee\u8868\uff0c\u6bd4\u4f7f\u7528\u7d22\u5f15\u5e76\u901a\u8fc7 <code>rowid<\/code> \u53bb\u626b\u63cf\u8868\u8981\u5feb 5 \u500d\u3002<\/p>\n<\/li>\n<li>\n<p><code>\/*+ INDEX_FFS(TABLE INDEX_NAME) *\/<\/code>\uff1a\u5bf9\u6307\u5b9a\u7684\u8868\u6267\u884c\u5feb\u901f\u5168\u7d22\u5f15\u626b\u63cf\uff0c\u800c\u4e0d\u662f\u5168\u8868\u626b\u63cf\u7684\u529e\u6cd5\u3002\u8981\u6c42\u8981\u68c0\u7d22\u7684\u5217\u90fd\u5728\u7d22\u5f15\u91cc\uff0c\u5982\u679c\u8868\u6709\u5f88\u591a\u5217\u65f6\u7279\u522b\u9002\u7528\u8be5\u63d0\u793a\u3002<\/p>\n<\/li>\n<li>\n<p><code>\/*+ NO_EXPAND *\/<\/code>\uff1a\u5bf9\u4e8e <code>WHERE<\/code> \u540e\u9762\u7684 <code>OR<\/code> \u6216\u8005 <code>IN-LIST<\/code> \u7684\u67e5\u8be2\u8bed\u53e5\uff0c<code>NO_EXPAND<\/code> \u5c06\u963b\u6b62\u5176\u57fa\u4e8e\u4f18\u5316\u5668\u5bf9\u5176\u8fdb\u884c\u6269\u5c55\uff0c\u7f29\u77ed\u89e3\u6790\u65f6\u95f4\u3002<\/p>\n<\/li>\n<li>\n<p><code>\/*+ CACHE(TABLE) *\/<\/code> \u548c <code>\/*+ NOCACHE(TABLE) *\/<\/code>\uff1a\u5f53\u8fdb\u884c\u5168\u8868\u626b\u63cf\u65f6\uff0c<code>CACHE<\/code> \u63d0\u793a\u80fd\u591f\u5c06\u8868\u5168\u90e8\u7f13\u5b58\u5230\u5185\u5b58\u4e2d\uff0c\u8fd9\u6837\u8bbf\u95ee\u540c\u4e00\u4e2a\u8868\u7684\u7528\u6237\u53ef\u76f4\u63a5\u5728\u5185\u5b58\u4e2d\u67e5\u627e\u6570\u636e\u3002\u6bd4\u8f83\u9002\u5408\u6570\u636e\u91cf\u5c0f\u4f46\u5e38\u88ab\u8bbf\u95ee\u7684\u8868\uff0c\u4e5f\u53ef\u4ee5\u5efa\u8868\u65f6\u6307\u5b9a <code>cache<\/code> \u9009\u9879\u8fd9\u6837\u5728\u7b2c\u4e00\u6b21\u8bbf\u95ee\u65f6\u5c31\u53ef\u4ee5\u5bf9\u5176\u7f13\u5b58\u3002 <code>NOCACHE<\/code> \u5219\u8868\u793a\u5bf9\u5df2\u7ecf\u6307\u5b9a\u4e86 <code>CACHE<\/code> \u9009\u9879\u7684\u8868\u4e0d\u8fdb\u884c\u7f13\u5b58\u3002<\/p>\n<\/li>\n<li>\n<p><code>\/*+ INDEX_SS(TABLE INDEX1,INDEX2) *\/<\/code>\uff1a\u6307\u793a\u5bf9\u7279\u5b9a\u8868\u7684\u7d22\u5f15\u4f7f\u7528\u8df3\u8dc3\u626b\u63cf,\u5373\u5f53\u7ec4\u5408\u7d22\u5f15\u7684\u7b2c\u4e00\u5217\u4e0d\u5728 <code>where<\/code> \u5b50\u53e5\u4e2d\u65f6,\u8ba9\u5176\u4f7f\u7528\u8be5\u7d22\u5f15\u3002<\/p>\n<\/li>\n<li>\n<p><code>\/*+ PUSH_SUBQ *\/<\/code>\uff1a\u5f53SQL\u91cc\u7528\u5230\u4e86\u5b50\u67e5\u8be2\u4e14\u8fd4\u56de\u76f8\u5bf9\u5c11\u7684\u884c\u65f6\uff0c\u8be5\u63d0\u793a\u53ef\u4ee5\u5c3d\u53ef\u80fd\u65e9\u5bf9\u5b50\u67e5\u8be2\u8fdb\u884c\u8bc4\u4f30\u4ece\u800c\u6539\u5584\u6027\u80fd\uff0c\u4e0d\u9002\u7528\u4e8e\u5408\u5e76\u8fde\u63a5\u6216\u5e26\u8fdc\u7a0b\u8868\u7684\u8fde\u63a5\u3002<\/p>\n<\/li>\n<\/ol>\n<hr\/>\n<p>\u6b22\u8fce\u5173\u6ce8\u6211\u7684\u5fae\u4fe1\u516c\u4f17\u53f7: <strong>coderbee\u7b14\u8bb0<\/strong>\uff0c\u53ef\u4ee5\u66f4\u53ca\u65f6\u56de\u590d\u4f60\u7684\u8ba8\u8bba\u3002<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"258\" height=\"258\" src=\"https:\/\/coderbee.net\/wp-content\/uploads\/2019\/01\/coderbee-note.jpg\" class=\"alignnone size-full wp-image-1707\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u516c\u53f8\u7684DBA\u8981\u6c42\u628a\u4ed6\u4eec\u56fa\u5316\u7684\u6267\u884c\u8ba1\u5212\u6539\u7528 Oracle hint \u6765\u5b9e\u73b0\uff0c\u6b63\u597d\u4e86 &hellip; <a href=\"https:\/\/coderbee.net\/index.php\/db\/20150117\/1146\">\u7ee7\u7eed\u9605\u8bfb <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[212],"_links":{"self":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/1146"}],"collection":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/comments?post=1146"}],"version-history":[{"count":6,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/1146\/revisions"}],"predecessor-version":[{"id":1153,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/1146\/revisions\/1153"}],"wp:attachment":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/media?parent=1146"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/categories?post=1146"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/tags?post=1146"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}