dbms_stats\u80fd\u826f\u597d\u5730\u4f30\u8a08\u7d71\u8a08\u6578\u64da\uff08\u5c24\u5176\u662f\u91dd\u5c0d\u8f03\u5927\u7684\u5206\u5340\u8868\uff09\uff0c\u4e26\u80fd\u7372\u5f97\u66f4\u597d\u7684\u7d71\u8a08\u7d50\u679c\uff0c\u6700\u7d42\u5236\u5b9a\u51fa\u901f\u5ea6\u66f4\u5feb\u7684SQL\u57f7\u884c\u8a08\u5283\u3002<\/p>\n
\u3000\u3000exec dbms_stats.gather_schema_stats(<\/p>\n
\u3000\u3000ownname\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 => ‘SCOTT’,<\/p>\n
\u3000\u3000options\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 => ‘GATHER AUTO’,<\/p>\n
\u3000\u3000estimate_percent => dbms_stats.auto_sample_size,<\/p>\n
\u3000\u3000method_opt\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 => ‘for all columns size repeat’,<\/p>\n
\u3000\u3000degree\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 => 15<\/p>\n
\u3000\u3000)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u70ba\u4e86\u5145\u5206\u8a8d\u8b58dbms_stats\u7684\u597d\u8655\uff0c\u9700\u8981\u4ed4\u7d30\u9ad4\u6703\u6bcf\u58f9\u689d\u4e3b\u8981\u7684\u9810\u7de8\u8b6f\u6307\u4ee4\uff08directive\uff09\u3002\u4e0b\u9762\u8b93\u6211\u5011\u7814\u7a76\u6bcf\u58f9\u689d\u6307\u4ee4\uff0c\u4e26\u9ad4\u6703\u5982\u4f55\u7528\u5b83\u70ba\u57fa\u65bc\u4ee3\u50f9\u7684SQL\u512a\u5316\u5668\u6536\u96c6\u6700\u9ad8\u8cea\u91cf\u7684\u7d71\u8a08\u6578\u64da\u3002<\/p>\n
\u3000\u3000options\u53c3\u6578<\/p>\n
\u3000\u3000\u4f7f\u75284\u500b\u9810\u8a2d\u7684\u65b9\u6cd5\u4e4b\u58f9\uff0c\u9019\u500b\u9078\u9805\u80fd\u63a7\u5236Oracle\u7d71\u8a08\u7684\u5237\u65b0\u65b9\u5f0f\uff1a<\/p>\n
\u3000\u3000gather\u2014\u2014\u91cd\u65b0\u5206\u6790\u6574\u500b\u67b6\u69cb\uff08Schema\uff09\u3002<\/p>\n
\u3000\u3000gather empty\u2014\u2014\u53ea\u5206\u6790\u76ee\u524d\u9084\u6c92\u6709\u7d71\u8a08\u7684\u8868\u3002<\/p>\n
\u3000\u3000gather stale\u2014\u2014\u53ea\u91cd\u65b0\u5206\u6790\u4fee\u6539\u91cf\u8d85\u904e10%\u7684\u8868\uff08\u9019\u4e9b\u4fee\u6539\u5305\u62ec\u63d2\u5165\u3001\u66f4\u65b0\u548c\u522a\u9664\uff09\u3002<\/p>\n
\u3000\u3000gather auto\u2014\u2014\u91cd\u65b0\u5206\u6790\u7576\u524d\u6c92\u6709\u7d71\u8a08\u7684\u5c0d\u8c61\uff0c\u4ee5\u53ca\u7d71\u8a08\u6578\u64da\u904e\u671f\uff08\u8b8a\u81df\uff09\u7684\u5c0d\u8c61\u3002\u8a3b\u610f\uff0c\u4f7f\u7528gather auto\u985e\u4f3c\u65bc\u7d44\u5408\u4f7f\u7528gather stale\u548cgather empty\u3002<\/p>\n
\u3000\u3000\u8a3b\u610f\uff0c\u7121\u8ad6gather stale\u9084\u662fgather auto\uff0c\u90fd\u8981\u6c42\u9032\u884c\u76e3\u8996\u3002\u5982\u679c\u59b3\u57f7\u884c\u58f9\u500balter table xxx monitoring\u547d\u4ee4\uff0cOracle\u6703\u7528dba_tab_modifications\u8996\u5716\u4f86\u8ddf\u8e64\u767c\u751f\u8b8a\u52d5\u7684\u8868\u3002\u9019\u6a23\u58f9\u4f86\uff0c\u59b3\u5c31\u78ba\u5207\u5730\u77e5\u9053\uff0c\u81ea\u5f9e\u4e0a\u58f9\u6b21\u5206\u6790\u7d71\u8a08\u6578\u64da\u4ee5\u4f86\uff0c\u767c\u751f\u4e86\u591a\u5c11\u6b21\u63d2\u5165\u3001\u66f4\u65b0\u548c\u522a\u9664\u64cd\u4f5c\u3002<\/p>\n
\u3000\u3000estimate_percent\u9078\u9805<\/p>\n
\u3000\u3000estimate_percent\u53c3\u6578\u662f\u58f9\u7a2e\u6bd4\u8f03\u65b0\u7684\u8a2d\u8a08\uff0c\u5b83\u5141\u8a31Oracle\u7684dbms_stats\u5728\u6536\u96c6\u7d71\u8a08\u6578\u64da\u6642\uff0c\u81ea\u52d5\u4f30\u8a08\u8981\u91c7\u6a23\u7684\u58f9\u500bsegment\u7684\u6700\u4f73\u767e\u5206\u6bd4\uff1a<\/p>\n
\u3000\u3000estimate_percent => dbms_stats.auto_sample_size<\/p>\n
\u3000\u3000\u8981\u9a57\u8b49\u81ea\u52d5\u7d71\u8a08\u91c7\u6a23\u7684\u6e96\u78ba\u6027\uff0c\u59b3\u53ef\u6aa2\u8996dba_tables sample_size\u5217\u3002\u58f9\u500b\u6709\u8da3\u7684\u5730\u65b9\u662f\uff0c\u5728\u4f7f\u7528\u81ea\u52d5\u91c7\u6a23\u6642\uff0cOracle\u6703\u70ba\u58f9\u500b\u6a23\u672c\u5c3a\u5bf8\u9078\u64c75\u523020\u7684\u767e\u5206\u6bd4\u3002\u8a18\u4f4f\uff0c\u7d71\u8a08\u6578\u64da\u8cea\u91cf\u8d8a\u597d\uff0cCBO\u505a\u51fa\u7684\u6c7a\u5b9a\u8d8a\u597d\u3002<\/p>\n
\u3000\u3000method_opt\u9078\u9805<\/p>\n
\u3000\u3000method_opt\uff1afor table –\u53ea\u7d71\u8a08\u8868<\/p>\n
\u3000\u3000for all indexed columns –\u53ea\u7d71\u8a08\u6709\u7d22\u5f15\u7684\u8868\u5217<\/p>\n
\u3000\u3000for all indexes –\u53ea\u5206\u6790\u7d71\u8a08\u76f8\u95dc\u7d22\u5f15<\/p>\n
\u3000\u3000for all columns<\/p>\n
\u3000\u3000dbms_stats\u7684method_opt\u53c3\u6578\u5c24\u5176\u9069\u5408\u5728\u8868\u548c\u7d22\u5f15\u6578\u64da\u767c\u751f\u8b8a\u5316\u6642\u5237\u65b0\u7d71\u8a08\u6578\u64da\u3002method_opt\u53c3\u6578\u4e5f\u9069\u5408\u7528\u65bc\u5224\u65b7\u54ea\u4e9b\u5217\u9700\u8981\u76f4\u65b9\u5716\uff08histograms\uff09\u3002<\/p>\n
\u3000\u3000\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u7d22\u5f15\u5167\u7684\u5404\u500b\u503c\u7684\u5206\u5e03\u6703\u5f71\u97ffCBO\u662f\u4f7f\u7528\u58f9\u500b\u7d22\u5f15\u9084\u662f\u57f7\u884c\u58f9\u6b21\u5168\u8868\u6383\u63cf\u7684\u6c7a\u7b56\u3002\u4f8b\u5982\uff0c\u5047\u5982\u5728where\u5b50\u53e5\u4e2d\u6307\u5b9a\u7684\u503c\u7684\u6578\u91cf\u4e0d\u5c0d\u7a31\uff0c\u5168\u8868\u6383\u63cf\u5c31\u986f\u5f97\u6bd4\u7d22\u5f15\u8a2a\u554f\u66f4\u7d93\u6fdf\u3002<\/p>\n
\u3000\u3000\u5982\u679c\u59b3\u6709\u58f9\u500b\u9ad8\u5ea6\u50be\u659c\u7684\u7d22\u5f15\uff08\u67d0\u4e9b\u503c\u7684\u884c\u6578\u4e0d\u5c0d\u7a31\uff09\uff0c\u5c31\u53ef\u5275\u5efaOracle\u76f4\u65b9\u5716\u7d71\u8a08\u3002\u4f46\u5728\u73fe\u5be6\u4e16\u754c\u4e2d\uff0c\u51fa\u73fe\u9019\u7a2e\u60c5\u6cc1\u7684\u6a5f\u7387\u76f8\u7576\u5c0f\u3002\u4f7f\u7528CBO\u6642\uff0c\u6700\u5e38\u898b\u7684\u932f\u8aa4\u4e4b\u58f9\u5c31\u662f\u5728CBO\u7d71\u8a08\u4e2d\u4e0d\u5fc5\u8981\u5730\u5f15\u5165\u76f4\u65b9\u5716\u3002\u6839\u64da\u7d93\u9a57\uff0c\u53ea\u6709\u5728\u5217\u503c\u8981\u6c42\u5fc5\u9808\u4fee\u6539\u57f7\u884c\u8a08\u5283\u6642\uff0c\u624d\u61c9\u4f7f\u7528\u76f4\u65b9\u5716\u3002<\/p>\n
\u3000\u3000\u70ba\u4e86\u667a\u80fd\u5730\u751f\u6210\u76f4\u65b9\u5716\uff0cOracle\u70badbms_stats\u6e96\u5099\u4e86method_opt\u53c3\u6578\u3002\u5728method_opt\u5b50\u53e5\u4e2d\uff0c\u9084\u6709\u58f9\u4e9b\u91cd\u8981\u7684\u65b0\u9078\u9805\uff0c\u5305\u62ecskewonly\uff0crepeat\u548cauto\uff1a<\/p>\n
\u3000\u3000method_opt=>’for all columns size skewonly’<\/p>\n
\u3000\u3000method_opt=>’for all columns size repeat’<\/p>\n
\u3000\u3000method_opt=>’for all columns size auto’<\/p>\n
\u3000\u3000skewonly\u9078\u9805\u6703\u8017\u8cbb\u5927\u91cf\u8655\u7406\u6642\u9593\uff0c\u56e0\u70ba\u5b83\u8981\u6aa2\u67e5\u6bcf\u500b\u7d22\u5f15\u4e2d\u7684\u6bcf\u500b\u5217\u7684\u503c\u7684\u5206\u5e03\u60c5\u6cc1\u3002<\/p>\n
\u3000\u3000\u5047\u5982dbms_stat\u767c\u73fe\u58f9\u500b\u7d22\u5f15\u7684\u5404\u500b\u5217\u5206\u5e03\u5f97\u4e0d\u5747\u52fb\uff0c\u5c31\u6703\u70ba\u90a3\u500b\u7d22\u5f15\u5275\u5efa\u76f4\u65b9\u5716\uff0c\u5e6b\u52a9\u57fa\u65bc\u4ee3\u50f9\u7684SQL\u512a\u5316\u5668\u6c7a\u5b9a\u662f\u9032\u884c\u7d22\u5f15\u8a2a\u554f\uff0c\u9084\u662f\u9032\u884c\u5168\u8868\u6383\u63cf\u8a2a\u554f\u3002\u4f8b\u5982\uff0c\u5728\u58f9\u500b\u7d22\u5f15\u4e2d\uff0c\u5047\u5b9a\u6709\u58f9\u500b\u5217\u572850%\u7684\u884c\u4e2d\uff0c\u5982\u6e05\u55aeB\u6240\u793a\uff0c\u90a3\u9ebd\u70ba\u4e86\u6aa2\u7d22\u9019\u4e9b\u884c\uff0c\u5168\u8868\u6383\u63cf\u7684\u901f\u5ea6\u6703\u5feb\u65bc\u7d22\u5f15\u6383\u63cf\u3002<\/p>\n
\u3000\u3000–*************************************************************<\/p>\n
\u3000\u3000– SKEWONLY option\u2014Detailed analysis<\/p>\n
\u3000\u3000–<\/p>\n
\u3000\u3000– Use this method for a first-time analysis for skewed indexes<\/p>\n
\u3000\u3000– This runs a long time because all indexes are examined<\/p>\n
\u3000\u3000–*************************************************************<\/p>\n
\u3000\u3000begin<\/p>\n
\u3000\u3000dbms_stats.gather_schema_stats(<\/p>\n
\u3000\u3000ownname\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 => ‘SCOTT’,<\/p>\n
\u3000\u3000estimate_percent => dbms_stats.auto_sample_size,<\/p>\n
\u3000\u3000method_opt\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 => ‘for all columns size skewonly’,<\/p>\n
\u3000\u3000degree\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 => 7<\/p>\n
\u3000\u3000);<\/p>\n
\u3000\u3000end;<\/p>\n
\u3000\u3000\u91cd\u65b0\u5206\u6790\u7d71\u8a08\u6578\u64da\u6642\uff0c\u4f7f\u7528repeat\u9078\u9805\uff0c\u91cd\u65b0\u5206\u6790\u4efb\u52d9\u6240\u6d88\u8017\u7684\u8cc7\u6e90\u5c31\u6703\u5c11\u58f9\u4e9b\u3002\u4f7f\u7528repeat\u9078\u9805\uff08\u6e05\u55aeC\uff09\u6642\uff0c\u53ea\u6703\u70ba\u73fe\u6709\u7684\u76f4\u65b9\u5716\u91cd\u65b0\u5206\u6790\u7d22\u5f15\uff0c\u4e0d\u518d\u641c\u7d22\u5176\u4ed6\u76f4\u65b9\u5716\u6a5f\u6703\u3002\u5b9a\u671f\u91cd\u65b0\u5206\u6790\u7d71\u8a08\u6578\u64da\u6642\uff0c\u59b3\u61c9\u8a72\u91c7\u53d6\u9019\u7a2e\u65b9\u5f0f\u3002<\/p>\n
\u3000\u3000–**************************************************************<\/p>\n
\u3000\u3000– REPEAT OPTION – Only reanalyze histograms for indexes<\/p>\n
\u3000\u3000– that have histograms<\/p>\n
\u3000\u3000–<\/p>\n
\u3000\u3000– Following the initial analysis, the weekly analysis<\/p>\n
\u3000\u3000– job will use the \u201crepeat\u201d option. The repeat option<\/p>\n
\u3000\u3000– tells dbms_stats that no indexes have changed, and<\/p>\n
\u3000\u3000– it will only reanalyze histograms for<\/p>\n
\u3000\u3000– indexes that have histograms.<\/p>\n
\u3000\u3000–**************************************************************<\/p>\n
\u3000\u3000begin<\/p>\n
\u3000\u3000dbms_stats.gather_schema_stats(<\/p>\n
\u3000\u3000ownname\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 => ‘SCOTT’,<\/p>\n
\u3000\u3000estimate_percent => dbms_stats.auto_sample_size,<\/p>\n
\u3000\u3000method_opt\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 => ‘for all columns size repeat’,<\/p>\n
\u3000\u3000degree\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 => 7<\/p>\n
\u3000\u3000);<\/p>\n
\u3000\u3000end;<\/p>\n","protected":false},"excerpt":{"rendered":"
dbms_stats\u80fd\u826f\u597d\u5730\u4f30\u8a08\u7d71\u8a08\u6578\u64da\uff08\u5c24\u5176\u662f\u91dd\u5c0d\u8f03\u5927\u7684\u5206\u5340\u8868\uff09\uff0c\u4e26\u80fd\u7372\u5f97\u66f4\u597d\u7684\u7d71\u8a08\u7d50\u679c\uff0c\u6700\u7d42\u5236\u5b9a\u51fa\u901f\u5ea6\u66f4\u5feb […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[695,2748,696],"class_list":["post-1685","post","type-post","status-publish","format-standard","hentry","category-oracle","tag-dbms","tag-oracle","tag-stats"],"_links":{"self":[{"href":"https:\/\/www.killtest.hk\/index.php\/wp-json\/wp\/v2\/posts\/1685","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.killtest.hk\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.killtest.hk\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.killtest.hk\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.killtest.hk\/index.php\/wp-json\/wp\/v2\/comments?post=1685"}],"version-history":[{"count":0,"href":"https:\/\/www.killtest.hk\/index.php\/wp-json\/wp\/v2\/posts\/1685\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.killtest.hk\/index.php\/wp-json\/wp\/v2\/media?parent=1685"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.killtest.hk\/index.php\/wp-json\/wp\/v2\/categories?post=1685"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.killtest.hk\/index.php\/wp-json\/wp\/v2\/tags?post=1685"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}