{"id":1573,"date":"2017-09-28T18:39:06","date_gmt":"2017-09-28T10:39:06","guid":{"rendered":"http:\/\/coderbee.net\/?p=1573"},"modified":"2019-01-06T20:10:36","modified_gmt":"2019-01-06T12:10:36","slug":"%e3%80%8a%e6%95%b0%e6%8d%ae%e5%ba%93%e7%b4%a2%e5%bc%95%e8%ae%be%e8%ae%a1%e4%b8%8e%e4%bc%98%e5%8c%96%e3%80%8b%e7%ac%94%e8%ae%b0%e4%b8%80","status":"publish","type":"post","link":"https:\/\/coderbee.net\/index.php\/db\/20170928\/1573","title":{"rendered":"\u300a\u6570\u636e\u5e93\u7d22\u5f15\u8bbe\u8ba1\u4e0e\u4f18\u5316\u300b\u7b14\u8bb0\u4e00"},"content":{"rendered":"<h1>\u7b2c\u4e8c\u7ae0 \u8868\u548c\u7d22\u5f15\u7ed3\u6784<\/h1>\n<p><img decoding=\"async\" src=\"\/\/coderbee.net\/wp-content\/uploads\/2017\/09\/B-Tree-index.jpg\" alt=\"B-Tree-index\" \/><\/p>\n<h3>\u7d22\u5f15\u9875\u548c\u8868\u9875<\/h3>\n<p>\u76ee\u524d\u9875\u7684\u5927\u5c0f\u4e00\u822c\u662f <code>32K<\/code> \u6216 <code>64K<\/code> \u7684\u3002\u9875\u7684\u5927\u5c0f\u51b3\u5b9a\u4e86\u4e00\u4e2a\u9875\u53ef\u4ee5\u5b58\u50a8\u591a\u5c11\u4e2a\u7d22\u5f15\u884c\u3001\u8868\u884c\uff0c\u4ee5\u53ca\u4e00\u5171\u9700\u8981\u591a\u5c11\u4e2a\u9875\u6765\u5b58\u50a8\u8868\u6216\u8005\u7d22\u5f15\u3002\u6bcf\u4e2a\u9875\u90fd\u4f1a\u9884\u7559\u4e00\u5b9a\u6bd4\u4f8b\u7684\u7a7a\u95f2\u7a7a\u95f4\uff0c\u4ee5\u6ee1\u8db3\u5411\u5176\u6dfb\u52a0\u65b0\u7684\u884c\u3002<strong>\u7f13\u51b2\u6c60\u548c I\/O \u6d3b\u52a8\u90fd\u662f\u57fa\u4e8e\u9875\u7684<\/strong>\u3002<\/p>\n<h3>\u7d22\u5f15\u884c<\/h3>\n<p>\u5bf9\u4e8e\u552f\u4e00\u7d22\u5f15\uff0c\u4e00\u4e2a\u7d22\u5f15\u884c\u7b49\u540c\u4e8e\u53f6\u5b50\u9875\u4e2d\u7684\u4e00\u4e2a\u7d22\u5f15\u6761\u76ee\u3002\u5b57\u6bb5\u503c\u6ca1\u8868\u4e2d\u590d\u5236\u5230\u7d22\u5f15\u4e0a\uff0c\u5e76\u52a0\u4e0a\u4e00\u4e2a\u6307\u5411\u8868\u4e2d\u8bb0\u5f55\u7684\u6307\u9488\u3002<\/p>\n<p>\u5bf9\u4e8e\u975e\u552f\u4e00\u7d22\u5f15\uff0c\u4e00\u4e2a\u7d22\u5f15\u503c\u540e\u5e26\u7740\u591a\u4e2a\u6307\u9488\uff0c\u6307\u9488\u6307\u5411\u4e0b\u4e00\u5c42\u975e\u53f6\u5b50\u9875\u6216\u53f6\u5b50\u9875\uff0c\u53f6\u5b50\u9875\u7684\u6307\u9488\u6307\u5411\u8868\u4e2d\u7684\u8bb0\u5f55\u3002<\/p>\n<h3>B \u6811\u7d22\u5f15\u7ed3\u6784<\/h3>\n<p>\u975e\u53f6\u5b50\u9875\u5305\u542b\u7740\u4e00\u4e2a\u952e\u503c\uff0c\u4ee5\u53ca\u4e00\u4e2a\u6307\u5411\u4e0b\u4e00\u5c42\u7ea7\u9875\u7684\u6307\u9488\uff0c\u8be5\u952e\u503c\u662f\u4e0b\u4e00\u5c42\u7ea7\u9875\u4e2d\u7684\u6700\u5927\u952e\u503c\u3002\u591a\u4e2a\u7d22\u5f15\u5c42\u7ea7\u6309\u7167\u8fd9\u4e00\u65b9\u5f0f\u9010\u5c42\u5efa\u7acb\uff0c\u76f4\u5230\u6839\u9875\u3002<\/p>\n<p><strong>\uff08\u5bf9\u4e8e\u975e\u552f\u4e00\u7d22\u5f15\uff09\u901a\u8fc7\u8fd9\u79cd\u65b9\u5f0f\u6765\u67e5\u627e\u4efb\u4f55\u4e00\u6761\u7d22\u5f15\u8bb0\u5f55\u90fd\u9700\u8981\u8bbf\u95ee\u76f8\u540c\u6570\u91cf\u7684\u975e\u53f6\u5b50\u9875\u3002<\/strong><\/p>\n<h1>\u7b2c\u4e09\u7ae0 SQL \u5904\u7406\u8fc7\u7a0b<\/h1>\n<p>\u8c13\u8bcd\u662f\u7d22\u5f15\u8bbe\u8ba1\u7684\u4e3b\u8981\u5165\u624b\u70b9\u3002<\/p>\n<h1>\u7b2c\u56db\u7ae0 \u4e3a select \u8bed\u53e5\u521b\u5efa\u7406\u60f3\u7684\u7d22\u5f15<\/h1>\n<p>\u4e09\u661f\u7d22\u5f15\u8bc4\u5b9a\uff1a<\/p>\n<ul>\n<li>\u7b2c\u4e00\u9897\u661f\uff1a\u4e0e\u67e5\u8be2\u76f8\u5173\u7684\u7d22\u5f15\u884c\u662f\u76f8\u90bb\u7684\uff0c\u6216\u8005\u81f3\u5c11\u76f8\u8ddd\u8db3\u591f\u9760\u8fd1\u3002<strong>\u6700\u5c0f\u5316\u4e86\u5fc5\u987b\u626b\u63cf\u7684\u7d22\u5f15\u7247\u7684\u5bbd\u5ea6\u3002<\/strong><\/li>\n<li>\u7b2c\u4e8c\u9897\u661f\uff1a\u7d22\u5f15\u884c\u7684\u987a\u5e8f\u4e0e\u67e5\u8be2\u8bed\u53e5\u7684\u9700\u6c42\u4e00\u81f4\u3002<strong>\u6392\u9664\u4e86\u6392\u5e8f\u64cd\u4f5c\u3002<\/strong><\/li>\n<li>\u7b2c\u4e09\u9897\u661f\uff1a\u7d22\u5f15\u884c\u5305\u542b\u67e5\u8be2\u8bed\u53e5\u4e2d\u7684\u6240\u6709\u5217\u3002<strong>\u907f\u514d\u4e86\u56de\u8868\u3002<\/strong><\/li>\n<\/ul>\n<blockquote>\n<p><strong>\u5bbd\u7d22\u5f15<\/strong>\uff1a\u6b3e\u7d22\u5f15\u662f\u6307\u4e00\u4e2a\u81f3\u5c11\u6ee1\u8db3\u4e86\u7b2c\u4e09\u9897\u661f\u7684\u7d22\u5f15\u3002\u8be5\u7d22\u5f15\u5305\u542b\u4e86 select \u8bed\u53e5\u6240\u6d89\u53ca\u7684\u6240\u6709\u5217\uff0c\u56e0\u6b64\u80fd\u591f\u4f7f\u5f97\u67e5\u8be2\u53ea\u9700\u8bbf\u95ee\u7d22\u5f15\u800c\u65e0\u987b\u56de\u8868\u3002<\/p>\n<\/blockquote>\n<p><!--more--><\/p>\n<h1>\u7b2c\u4e94\u7ae0 \u524d\u77bb\u6027\u7684\u7d22\u5f15\u8bbe\u8ba1<\/h1>\n<h2>\u57fa\u672c\u95ee\u9898\u6cd5\uff08BQ\uff09\uff1a<\/h2>\n<blockquote>\n<p>\u95ee\u9898\uff1a\u662f\u5426\u6709\u4e00\u4e2a\u5df2\u5b58\u5728\u7684\u6216\u8ba1\u5212\u4e2d\u7684\u7d22\u5f15\u5305\u542b\u4e86 where \u5b50\u53e5\u6240\u5f15\u7528\u7684\u6240\u6709\u5217\uff08\u4e00\u4e2a\u534a\u5bbd\u7d22\u5f15\uff09\uff1f<\/p>\n<\/blockquote>\n<ol>\n<li>\u5982\u679c\u7b54\u6848\u662f\u5426\uff0c\u9996\u5148\u8003\u8651\u5c06\u7f3a\u5c11\u7684\u6240\u6709\u8c13\u8bcd\u5217\u6dfb\u52a0\u5230\u4e00\u4e2a\u73b0\u6709\u7684\u7d22\u5f15\u4e0a\u53bb\u3002\u8fd9\u5c06\u4ea7\u751f\u4e00\u4e2a<strong>\u534a\u5bbd\u7d22\u5f15\uff0c\u5c3d\u7ba1\u7d22\u5f15\u7684\u7b49\u503c\u5339\u914d\u8fc7\u7a0b\u5e76\u4e0d\u4ee4\u4eba\u6ee1\u610f\uff08\u4e00\u661f\uff09\uff0c\u4f46\u662f\u7d22\u5f15\u8fc7\u6ee4\u53ef\u4ee5\u786e\u4fdd\u56de\u8868\u8bbf\u95ee\u53ea\u53d1\u751f\u5728\u6240\u6709\u67e5\u8be2\u6761\u4ef6\u90fd\u6ee1\u8db3\u7684\u65f6\u5019<\/strong>\u3002<\/li>\n<li>\u5982\u679c\u8fd9\u8fd8\u6ca1\u8fbe\u5230\u8db3\u591f\u7684\u6027\u80fd\uff0c\u90a3\u4e48\u4e0b\u4e00\u4e2a\u9009\u62e9\u662f\u5c06\u6240\u6709\u6d89\u53ca\u7684\u5217\u90fd\u52a0\u5230\u7d22\u5f15\u4e0a\u53bb\uff0c\u4ee5\u4f7f\u8bbf\u95ee\u8def\u5f84\u53ea\u9700\u8bbf\u95ee\u7d22\u5f15\u3002\u8fd9\u5c06\u4ea7\u751f\u4e00\u4e2a<strong>\u907f\u514d\u6240\u6709\u8868\u8bbf\u95ee\u7684\u5bbd\u7d22\u5f15<\/strong>\u3002<\/li>\n<li>\u5982\u679c select \u4ecd\u7136\u4e0d\u80fd\u6ee1\u8db3\u6027\u80fd\u8981\u6c42\uff0c\u5219\u8981\u8bbe\u8ba1\u4e00\u4e2a \u4e09\u661f\u7d22\u5f15\u3002<\/li>\n<\/ol>\n<h2>\u5feb\u901f\u4e0a\u9650\u8bc4\u4f30\u6cd5\uff08QUBE\uff09<\/h2>\n<pre><code>\u6bd4\u8f83\u503c\uff1a\nLRT = TR * 10ms + TS * 10ms\n\n\u7edd\u5bf9\u503c\uff1a\nLRT = TR * 10ms + TS * 0.01ms + F * 0.1ms\n\nLRT = \u672c\u5730\u54cd\u5e94\u65f6\u95f4\nTR  = \u968f\u673a\u8bbf\u95ee\u7684\u6570\u91cf\nTS  = \u987a\u5e8f\u8bbf\u95ee\u7684\u6570\u91cf\nF   = \u6709\u6548 FETCH \u7684\u6570\u91cf\n<\/code><\/pre>\n<blockquote>\n<p>\u6ce8\uff1a\u4e0a\u9762\u7684\u6beb\u79d2\u6570\u662f\u6839\u636e\u786c\u76d8\u8f6c\u901f\u4e3a 15000 \u8f6c\u6bcf\u5206\u949f\u8ba1\u7b97\u7684\u3002<code>10ms<\/code> \u7684\u7ec4\u6210\u4e3a: \u6392\u961f<code>3ms<\/code> + \u5bfb\u9053<code>4ms<\/code> + \u5355\u5708\u65cb\u8f6c<code>2ms<\/code> + \u4f20\u8f93 <code>1ms<\/code>\u3002<\/p>\n<\/blockquote>\n<h2>\u534a\u5bbd\u7d22\u5f15\u3001\u5bbd\u7d22\u5f15<\/h2>\n<ul>\n<li>\n<p>\u534a\u5bbd\u7d22\u5f15\uff1a\u5305\u542b\u4e86 where \u5b50\u53e5\u7684\u6240\u6709\u5217\uff0c\u80fd\u6700\u5927\u5316\u5229\u7528\u7d22\u5f15\u7684\u5217\u8fdb\u884c\u8fc7\u6ee4\uff1b<\/p>\n<\/li>\n<li>\n<p>\u534a\u5bbd\u7d22\u5f15\uff1a\u5305\u542b\u4e86 where\/select \u5b50\u53e5\u7684\u6240\u6709\u5217\uff0c\u80fd\u6700\u5927\u5316\u5229\u7528\u7d22\u5f15\u7684\u5217\u8fdb\u884c\u8fc7\u6ee4\uff1b\u540c\u65f6\u8fd4\u56de\u7684\u6570\u636e\u5c31\u5728\u7d22\u5f15\u4e0a\uff0c\u4e0d\u9700\u8981\u56de\u8868\uff0c<strong>\u53ea\u9700\u8bbf\u95ee\u7d22\u5f15<\/strong>\u3002<\/p>\n<\/li>\n<\/ul>\n<h1>\u7b2c\u516d\u7ae0 \u5f71\u54cd\u7d22\u5f15\u8bbe\u8ba1\u8fc7\u7a0b\u7684\u56e0\u7d20<\/h1>\n<ul>\n<li>\n<p>\u591a\u4e2a\u7a84\u7247\u7d22\u5f15\uff1a\u8ba9\u6570\u636e\u5e93\u8fdb\u884c\u7d22\u5f15\u626b\u63cf\u5408\u5e76\u3002<\/p>\n<\/li>\n<li>\n<p>\u56f0\u96be\u8c13\u8bcd\uff1a\u8ba9\u6570\u636e\u5e93\u65e0\u6cd5\u8fdb\u884c\u7d22\u5f15\u7247\u5b9a\u4e49\u7684\u8c13\u8bcd\u3002\u6bd4\u5982\u51fd\u6570\u4e2d\u7684\u8c13\u8bcd\u3001not \u51fd\u6570\u3001 or \u8fde\u63a5\u7684\u591a\u4e2a\u5217\u7684\u8c13\u8bcd \u7b49\u3002<\/p>\n<\/li>\n<li>\n<p>\u8fc7\u6ee4\u56e0\u5b50\u9690\u60a3\uff1a\u8981<strong>\u5173\u6ce8\u6700\u7cdf\u7cd5\u7684\u573a\u666f<\/strong>\u3002\u4e0d\u540c\u8fc7\u6ee4\u56e0\u5b50\u5bf9\u7ed3\u679c\u96c6\u7684\u5f71\u54cd\u975e\u5e38\u5927\uff0c\u6bd4\u5982\u4e0d\u540c\u72b6\u6001\u4e0b\u7684\u6570\u636e\u91cf\u7ea7\u662f\u5dee\u522b\u5f88\u5927\u7684\u3002<\/p>\n<\/li>\n<\/ul>\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<br \/>\n<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>\u7b2c\u4e8c\u7ae0 \u8868\u548c\u7d22\u5f15\u7ed3\u6784 \u7d22\u5f15\u9875\u548c\u8868\u9875 \u76ee\u524d\u9875\u7684\u5927\u5c0f\u4e00\u822c\u662f 32K \u6216 64K \u7684\u3002 &hellip; <a href=\"https:\/\/coderbee.net\/index.php\/db\/20170928\/1573\">\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":[291,215],"_links":{"self":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/1573"}],"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=1573"}],"version-history":[{"count":10,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/1573\/revisions"}],"predecessor-version":[{"id":1740,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/1573\/revisions\/1740"}],"wp:attachment":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/media?parent=1573"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/categories?post=1573"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/tags?post=1573"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}