{"id":1322,"date":"2016-01-14T14:27:16","date_gmt":"2016-01-14T06:27:16","guid":{"rendered":"http:\/\/www.821121.com\/?p=1322"},"modified":"2021-01-07T14:36:07","modified_gmt":"2021-01-07T06:36:07","slug":"%e5%ad%a6%e4%b9%a0%e7%ac%94%e8%ae%b0%e4%b9%8bsql-partial-range-scan","status":"publish","type":"post","link":"http:\/\/www.821121.com\/?p=1322","title":{"rendered":"\u5b66\u4e60\u7b14\u8bb0\u4e4bSQL-Partial Range Scan 1"},"content":{"rendered":"<h1>Partial Range Scan<\/h1>\n<h4>What\u2019s Partial Range Scan<\/h4>\n<p>The Partial Range Scan doesn\u2019t mean to scan all the data that meet the conditions (predicates) in the SQL Where clause; instead it means that the SQL engine doesn\u2019t need to scan all the data before returning the first set of data to the users. This is similar to what the optimizer mode \u201cFIRST_ROWS\u201d indicates.<br \/>\nPartial Range Scan is very helpful for the OLTP operations, but this doesn\u2019t mean the partial range scan cannot be used in the batch process operations.<br \/>\nPartial Range Scan can reduce the data volume that need to scan and to what extent the data volume that the Partial Range Scan need to scan is not impacted by the data volume that meets the conditions (predicates) in the WHERE clause. This is the charming characteristic of the Partial Range Scan.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Partial Range Scan What\u2019s<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[18,48],"tags":[],"class_list":["post-1322","post","type-post","status-publish","format-standard","hentry","category-oracle-11g","category-sql"],"_links":{"self":[{"href":"http:\/\/www.821121.com\/index.php?rest_route=\/wp\/v2\/posts\/1322","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.821121.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.821121.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.821121.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.821121.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1322"}],"version-history":[{"count":2,"href":"http:\/\/www.821121.com\/index.php?rest_route=\/wp\/v2\/posts\/1322\/revisions"}],"predecessor-version":[{"id":1326,"href":"http:\/\/www.821121.com\/index.php?rest_route=\/wp\/v2\/posts\/1322\/revisions\/1326"}],"wp:attachment":[{"href":"http:\/\/www.821121.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1322"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.821121.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1322"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.821121.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1322"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}