{"id":2037,"date":"2020-07-29T23:21:29","date_gmt":"2020-07-29T15:21:29","guid":{"rendered":"http:\/\/39.97.231.10\/?p=2037"},"modified":"2020-07-29T23:21:29","modified_gmt":"2020-07-29T15:21:29","slug":"mysql-%e7%8a%b6%e6%80%81%e5%8f%98%e9%87%8fhandler_read_next","status":"publish","type":"post","link":"http:\/\/www.weijing.co\/?p=2037","title":{"rendered":"MySQL \u72b6\u6001\u53d8\u91cfHandler_read_next"},"content":{"rendered":"<div>\n<div>\n<div>\nMySQL\u6709\u5f88\u591a\u72b6\u6001\u53d8\u91cf\uff0c\u6bcf\u4e2a\u72b6\u6001\u53d8\u91cf\u90fd\u6709\u5176\u80cc\u540e\u6240\u4ee3\u8868\u7684\u610f\u4e49\uff0c\u672c\u6587\u4ecb\u7ecd\u72b6\u6001\u53d8\u91cfHandler_read_next\u53ca\u5728\u54ea\u4e9b\u573a\u666f\u4e2d\uff0c\u8fd9\u4e2a\u72b6\u6001\u53d8\u91cf\u7684\u503c\u4f1a\u663e\u8457\u589e\u957f\u3002<\/p>\n<h4>\u4e00\u3001Handler_read_next\u5b98\u65b9\u6587\u6863\u63cf\u8ff0\uff1a<\/h4>\n<p>Handler_read_next<br \/>\nThe number of requests to read the next row in key order. This value is incremented if you are querying an index column with a range constraint or if you are doing an index scan.<br \/>\n\u7ffb\u8bd1\u6210\u4e2d\u6587\uff0c\u5927\u6982\u610f\u601d\u662f\u6309\u7167\u7d22\u5f15\u987a\u5e8f\u8bfb\u53d6\u884c\u8bb0\u5f55\u7684\u6570\u91cf\uff0c\u8fd9\u662f\u4e00\u4e2a\u7d2f\u8ba1\u503c\uff0c\u5982\u679c\u6309\u8303\u56f4\u67e5\u8be2\u4e00\u4e2a\u7d22\u5f15\u6216\u8005\u505a\u4e00\u4e2a\u7d22\u5f15\u626b\u63cf\uff0c\u5c31\u4f1a\u5bfc\u81f4\u8fd9\u4e2a\u503c\u589e\u957f\u3002<\/p>\n<h4>\u4e8c\u3001Handler_read_next\u573a\u666f\u6d4b\u8bd5\uff1a<\/h4>\n<p>\u4e0b\u9762\u505a\u51e0\u4e2a\u5b9e\u9a8c\uff0c\u89c2\u5bdf\u4e00\u4e0bHandler_read_next\u503c\u7684\u589e\u957f\u60c5\u51b5\u3002<br \/>\nMySQL\u7248\u672c\uff1a5.7.19<br \/>\n\u8868t1\uff0c3\u4e2a\u5b57\u6bb5\u5206\u522b\u4e3aid,name,age\uff0c\u5176\u4e2did\u4e3a\u81ea\u589e\u4e3b\u952e\uff0c\u8868\u4e2d\u4e00\u5171\u6709\u8bb0\u5f5512289\u3002<\/p>\n<h5>\u5168\u8868\u626b\u63cf\uff1a<\/h5>\n<p>flush status; \u91cd\u7f6e\u6240\u6709\u72b6\u6001\u53d8\u91cf\u4e3a0\u3002<br \/>\n\u6267\u884c select count(*) from t1 where age = 21;<br \/>\nage\u5217\u6ca1\u6709\u7d22\u5f15\uff0cSQL\u8d70\u5168\u8868\u626b\u63cf\uff0c\u7b49\u503c\u67e5\u8be2\uff0cHandler_read_next \u4e3a0\u3002<br \/>\n\u5168\u8868\u626b\u63cf\uff0c\u8303\u56f4\u67e5\u8be2\uff1a<br \/>\nselect count(*) from t1 where age &gt;5 and age &lt; 20;<br \/>\nHandler_read_next \u4e3a0\u3002<\/p>\n<h5>\u4e3b\u952e\u7d22\u5f15\u6216\u8005\u552f\u4e00\u7d22\u5f15\uff1a<\/h5>\n<p>flush status; \u91cd\u7f6e\u6240\u6709\u72b6\u6001\u53d8\u91cf\u4e3a0\u3002<br \/>\n\u6267\u884c select count(*) from t1 where id = 21;<br \/>\n\u8d70\u4e3b\u952e\u7d22\u5f15\u6216\u8005\u552f\u4e00\u7d22\u5f15\uff0cHandler_read_next \u4e3a0\u3002<br \/>\n\u8303\u56f4\u67e5\u8be2\uff1a<br \/>\nselect count(*) from t1 where id &gt;5 and id &lt; 20;<br \/>\nHandler_read_next \u4e3a 13\uff0c\u4e0e\u6ee1\u8db3\u6761\u4ef6\u7684\u8bb0\u5f55\u6570\u4e00\u81f4\u3002<\/p>\n<h5>\u975e\u552f\u4e00\u7d22\u5f15\uff1a<\/h5>\n<p>\u5728age\u5b57\u6bb5\u4e0a\u6dfb\u52a0\u975e\u552f\u4e00\u7d22\u5f15\u3002<br \/>\nflush status; \u91cd\u7f6e\u6240\u6709\u72b6\u6001\u53d8\u91cf\u4e3a0\u3002<br \/>\nselect count(*) from t1 where age =12;<br \/>\nHandler_read_next \u4e3a 2049\uff0c\u4e0e\u6ee1\u8db3\u6761\u4ef6\u7684\u8bb0\u5f55\u6570\u4e00\u81f4\u3002<br \/>\n\u8303\u56f4\u67e5\u8be2\uff1a<br \/>\nselect count(*) from t1 where age &gt;5 and age &lt; 20;<br \/>\nHandler_read_next \u4e3a 12289\uff0c\u4e0e\u6ee1\u8db3\u6761\u4ef6\u7684\u8bb0\u5f55\u6570\u4e00\u81f4\u3002<\/p>\n<h4>\u4e09\u3001\u603b\u7ed3\uff1a<\/h4>\n<p>MySQL \u7684 Handler_read_next \u72b6\u6001\u53d8\u91cf\u8bb0\u5f55\u4e0b\u5217\u573a\u666f\u4e0b\u7684\u7d22\u5f15\u626b\u63cf\u8bb0\u5f55\u6570\u3002<\/p>\n<ul>\n<li>\u4e3b\u952e\u7d22\u5f15\u7684\u8303\u56f4\u67e5\u8be2\u3002<\/li>\n<li>\u552f\u4e00\u7d22\u5f15\u7684\u8303\u56f4\u67e5\u8be2<\/li>\n<li>\u975e\u552f\u4e00\u7d22\u5f15\u7684\u7b49\u503c\u67e5\u8be2<\/li>\n<li>\u975e\u552f\u4e00\u7d22\u5f15\u7684\u8303\u56f4\u67e5\u8be2<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>MySQL\u6709\u5f88\u591a\u72b6\u6001\u53d8\u91cf\uff0c\u6bcf\u4e2a\u72b6\u6001\u53d8\u91cf\u90fd\u6709\u5176\u80cc\u540e\u6240\u4ee3\u8868\u7684\u610f\u4e49\uff0c\u672c\u6587\u4ecb\u7ecd\u72b6\u6001\u53d8\u91cfHandler_read_nex &hellip;<\/p>\n<p class=\"read-more\"> <a class=\"\" href=\"http:\/\/www.weijing.co\/?p=2037\"> <span class=\"screen-reader-text\">MySQL \u72b6\u6001\u53d8\u91cfHandler_read_next<\/span> \u67e5\u770b\u5168\u6587 &raquo;<\/a><\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"default","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":""},"categories":[90,88],"tags":[],"uagb_featured_image_src":{"full":false,"thumbnail":false,"medium":false,"medium_large":false,"large":false,"1536x1536":false,"2048x2048":false,"mailpoet_newsletter_max":false,"woocommerce_thumbnail":false,"woocommerce_single":false,"woocommerce_gallery_thumbnail":false,"shop_catalog":false,"shop_single":false,"shop_thumbnail":false},"uagb_author_info":{"display_name":"weijing","author_link":"http:\/\/www.weijing.co\/?author=4"},"uagb_comment_info":0,"uagb_excerpt":"MySQL\u6709\u5f88\u591a\u72b6\u6001\u53d8\u91cf\uff0c\u6bcf\u4e2a\u72b6\u6001\u53d8\u91cf\u90fd\u6709\u5176\u80cc\u540e\u6240\u4ee3\u8868\u7684\u610f\u4e49\uff0c\u672c\u6587\u4ecb\u7ecd\u72b6\u6001\u53d8\u91cfHandler_read_nex&hellip;","_links":{"self":[{"href":"http:\/\/www.weijing.co\/index.php?rest_route=\/wp\/v2\/posts\/2037"}],"collection":[{"href":"http:\/\/www.weijing.co\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.weijing.co\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.weijing.co\/index.php?rest_route=\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"http:\/\/www.weijing.co\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2037"}],"version-history":[{"count":0,"href":"http:\/\/www.weijing.co\/index.php?rest_route=\/wp\/v2\/posts\/2037\/revisions"}],"wp:attachment":[{"href":"http:\/\/www.weijing.co\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2037"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.weijing.co\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2037"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.weijing.co\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2037"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}