{"id":272,"date":"2018-11-21T20:15:35","date_gmt":"2018-11-21T12:15:35","guid":{"rendered":"https:\/\/www.ccagml.com\/?p=272"},"modified":"2019-02-21T10:12:50","modified_gmt":"2019-02-21T02:12:50","slug":"mysql%e5%9f%ba%e7%a1%80%e7%9f%a5%e8%af%86","status":"publish","type":"post","link":"https:\/\/www.ccagml.com\/?p=272","title":{"rendered":"MySQL\u57fa\u7840\u77e5\u8bc6"},"content":{"rendered":"<ul>\n<li><a href=\"https:\/\/github.com\/CyC2018\/\" target=\"_blank\" rel=\"noopener\">\u53c2\u8003 <\/a><\/li>\n<\/ul>\n<h1>\u4e00\u3001\u7d22\u5f15<\/h1>\n<h2>B+ Tree \u539f\u7406<\/h2>\n<h3>1. \u6570\u636e\u7ed3\u6784<\/h3>\n<p>B Tree \u6307\u7684\u662f Balance Tree\uff0c\u4e5f\u5c31\u662f\u5e73\u8861\u6811\u3002\u5e73\u8861\u6811\u662f\u4e00\u9897\u67e5\u627e\u6811\uff0c\u5e76\u4e14\u6240\u6709\u53f6\u5b50\u8282\u70b9\u4f4d\u4e8e\u540c\u4e00\u5c42\u3002<\/p>\n<p>B+ Tree \u662f\u57fa\u4e8e B Tree \u548c\u53f6\u5b50\u8282\u70b9\u987a\u5e8f\u8bbf\u95ee\u6307\u9488\u8fdb\u884c\u5b9e\u73b0\uff0c\u5b83\u5177\u6709 B Tree \u7684\u5e73\u8861\u6027\uff0c\u5e76\u4e14\u901a\u8fc7\u987a\u5e8f\u8bbf\u95ee\u6307\u9488\u6765\u63d0\u9ad8\u533a\u95f4\u67e5\u8be2\u7684\u6027\u80fd\u3002<\/p>\n<p>\u5728 B+ Tree \u4e2d\uff0c\u4e00\u4e2a\u8282\u70b9\u4e2d\u7684 key \u4ece\u5de6\u5230\u53f3\u975e\u9012\u51cf\u6392\u5217\uff0c\u5982\u679c\u67d0\u4e2a\u6307\u9488\u7684\u5de6\u53f3\u76f8\u90bb key \u5206\u522b\u662f key<sub>i<\/sub> \u548c key<sub>i+1<\/sub>\uff0c\u4e14\u4e0d\u4e3a null\uff0c\u5219\u8be5\u6307\u9488\u6307\u5411\u8282\u70b9\u7684\u6240\u6709 key \u5927\u4e8e\u7b49\u4e8e key<sub>i<\/sub> \u4e14\u5c0f\u4e8e\u7b49\u4e8e key<sub>i+1<\/sub>\u3002<\/p>\n<div align=\"center\"> <img src=\"pics\/10a6d3ee-04b2-46b4-b171-d596e5ab0f84.jpg\"\/> <\/div>\n<p><\/p>\n<h3>2. \u64cd\u4f5c<\/h3>\n<p>\u8fdb\u884c\u67e5\u627e\u64cd\u4f5c\u65f6\uff0c\u9996\u5148\u5728\u6839\u8282\u70b9\u8fdb\u884c\u4e8c\u5206\u67e5\u627e\uff0c\u627e\u5230\u4e00\u4e2a key \u6240\u5728\u7684\u6307\u9488\uff0c\u7136\u540e\u9012\u5f52\u5730\u5728\u6307\u9488\u6240\u6307\u5411\u7684\u8282\u70b9\u8fdb\u884c\u67e5\u627e\u3002\u76f4\u5230\u67e5\u627e\u5230\u53f6\u5b50\u8282\u70b9\uff0c\u7136\u540e\u5728\u53f6\u5b50\u8282\u70b9\u4e0a\u8fdb\u884c\u4e8c\u5206\u67e5\u627e\uff0c\u627e\u51fa key \u6240\u5bf9\u5e94\u7684 data\u3002<\/p>\n<p>\u63d2\u5165\u5220\u9664\u64cd\u4f5c\u4f1a\u7834\u574f\u5e73\u8861\u6811\u7684\u5e73\u8861\u6027\uff0c\u56e0\u6b64\u5728\u63d2\u5165\u5220\u9664\u64cd\u4f5c\u4e4b\u540e\uff0c\u9700\u8981\u5bf9\u6811\u8fdb\u884c\u4e00\u4e2a\u5206\u88c2\u3001\u5408\u5e76\u3001\u65cb\u8f6c\u7b49\u64cd\u4f5c\u6765\u7ef4\u62a4\u5e73\u8861\u6027\u3002<\/p>\n<h3>3. \u4e0e\u7ea2\u9ed1\u6811\u7684\u6bd4\u8f83<\/h3>\n<p>\u7ea2\u9ed1\u6811\u7b49\u5e73\u8861\u6811\u4e5f\u53ef\u4ee5\u7528\u6765\u5b9e\u73b0\u7d22\u5f15\uff0c\u4f46\u662f\u6587\u4ef6\u7cfb\u7edf\u53ca\u6570\u636e\u5e93\u7cfb\u7edf\u666e\u904d\u91c7\u7528 B+ Tree \u4f5c\u4e3a\u7d22\u5f15\u7ed3\u6784\uff0c\u4e3b\u8981\u6709\u4ee5\u4e0b\u4e24\u4e2a\u539f\u56e0\uff1a<\/p>\n<p>\uff08\u4e00\uff09\u66f4\u5c11\u7684\u67e5\u627e\u6b21\u6570<\/p>\n<p>\u5e73\u8861\u6811\u67e5\u627e\u64cd\u4f5c\u7684\u65f6\u95f4\u590d\u6742\u5ea6\u548c\u6811\u9ad8 h \u76f8\u5173\uff0cO(h)=O(log<sub>d<\/sub>N)\uff0c\u5176\u4e2d d \u4e3a\u6bcf\u4e2a\u8282\u70b9\u7684\u51fa\u5ea6\u3002<\/p>\n<p>\u7ea2\u9ed1\u6811\u7684\u51fa\u5ea6\u4e3a 2\uff0c\u800c B+ Tree \u7684\u51fa\u5ea6\u4e00\u822c\u90fd\u975e\u5e38\u5927\uff0c\u6240\u4ee5\u7ea2\u9ed1\u6811\u7684\u6811\u9ad8 h \u5f88\u660e\u663e\u6bd4 B+ Tree \u5927\u975e\u5e38\u591a\uff0c\u67e5\u627e\u7684\u6b21\u6570\u4e5f\u5c31\u66f4\u591a\u3002<\/p>\n<p>\uff08\u4e8c\uff09\u5229\u7528\u78c1\u76d8\u9884\u8bfb\u7279\u6027<\/p>\n<p>\u4e3a\u4e86\u51cf\u5c11\u78c1\u76d8 I\/O \u64cd\u4f5c\uff0c\u78c1\u76d8\u5f80\u5f80\u4e0d\u662f\u4e25\u683c\u6309\u9700\u8bfb\u53d6\uff0c\u800c\u662f\u6bcf\u6b21\u90fd\u4f1a\u9884\u8bfb\u3002\u9884\u8bfb\u8fc7\u7a0b\u4e2d\uff0c\u78c1\u76d8\u8fdb\u884c\u987a\u5e8f\u8bfb\u53d6\uff0c\u987a\u5e8f\u8bfb\u53d6\u4e0d\u9700\u8981\u8fdb\u884c\u78c1\u76d8\u5bfb\u9053\uff0c\u5e76\u4e14\u53ea\u9700\u8981\u5f88\u77ed\u7684\u65cb\u8f6c\u65f6\u95f4\uff0c\u901f\u5ea6\u4f1a\u975e\u5e38\u5feb\u3002<\/p>\n<p>\u64cd\u4f5c\u7cfb\u7edf\u4e00\u822c\u5c06\u5185\u5b58\u548c\u78c1\u76d8\u5206\u5272\u6210\u56fa\u5b9a\u5927\u5c0f\u7684\u5757\uff0c\u6bcf\u4e00\u5757\u79f0\u4e3a\u4e00\u9875\uff0c\u5185\u5b58\u4e0e\u78c1\u76d8\u4ee5\u9875\u4e3a\u5355\u4f4d\u4ea4\u6362\u6570\u636e\u3002\u6570\u636e\u5e93\u7cfb\u7edf\u5c06\u7d22\u5f15\u7684\u4e00\u4e2a\u8282\u70b9\u7684\u5927\u5c0f\u8bbe\u7f6e\u4e3a\u9875\u7684\u5927\u5c0f\uff0c\u4f7f\u5f97\u4e00\u6b21 I\/O \u5c31\u80fd\u5b8c\u5168\u8f7d\u5165\u4e00\u4e2a\u8282\u70b9\u3002\u5e76\u4e14\u53ef\u4ee5\u5229\u7528\u9884\u8bfb\u7279\u6027\uff0c\u76f8\u90bb\u7684\u8282\u70b9\u4e5f\u80fd\u591f\u88ab\u9884\u5148\u8f7d\u5165\u3002<\/p>\n<h2>MySQL \u7d22\u5f15<\/h2>\n<p>\u7d22\u5f15\u662f\u5728\u5b58\u50a8\u5f15\u64ce\u5c42\u5b9e\u73b0\u7684\uff0c\u800c\u4e0d\u662f\u5728\u670d\u52a1\u5668\u5c42\u5b9e\u73b0\u7684\uff0c\u6240\u4ee5\u4e0d\u540c\u5b58\u50a8\u5f15\u64ce\u5177\u6709\u4e0d\u540c\u7684\u7d22\u5f15\u7c7b\u578b\u548c\u5b9e\u73b0\u3002<\/p>\n<h3>1. B+Tree \u7d22\u5f15<\/h3>\n<p>\u662f\u5927\u591a\u6570 MySQL \u5b58\u50a8\u5f15\u64ce\u7684\u9ed8\u8ba4\u7d22\u5f15\u7c7b\u578b\u3002<\/p>\n<p>\u56e0\u4e3a\u4e0d\u518d\u9700\u8981\u8fdb\u884c\u5168\u8868\u626b\u63cf\uff0c\u53ea\u9700\u8981\u5bf9\u6811\u8fdb\u884c\u641c\u7d22\u5373\u53ef\uff0c\u6240\u4ee5\u67e5\u627e\u901f\u5ea6\u5feb\u5f88\u591a\u3002<\/p>\n<p>\u9664\u4e86\u7528\u4e8e\u67e5\u627e\uff0c\u8fd8\u53ef\u4ee5\u7528\u4e8e\u6392\u5e8f\u548c\u5206\u7ec4\u3002<\/p>\n<p>\u53ef\u4ee5\u6307\u5b9a\u591a\u4e2a\u5217\u4f5c\u4e3a\u7d22\u5f15\u5217\uff0c\u591a\u4e2a\u7d22\u5f15\u5217\u5171\u540c\u7ec4\u6210\u952e\u3002<\/p>\n<p>\u9002\u7528\u4e8e\u5168\u952e\u503c\u3001\u952e\u503c\u8303\u56f4\u548c\u952e\u524d\u7f00\u67e5\u627e\uff0c\u5176\u4e2d\u952e\u524d\u7f00\u67e5\u627e\u53ea\u9002\u7528\u4e8e\u6700\u5de6\u524d\u7f00\u67e5\u627e\u3002\u5982\u679c\u4e0d\u662f\u6309\u7167\u7d22\u5f15\u5217\u7684\u987a\u5e8f\u8fdb\u884c\u67e5\u627e\uff0c\u5219\u65e0\u6cd5\u4f7f\u7528\u7d22\u5f15\u3002<\/p>\n<p>InnoDB \u7684 B+Tree \u7d22\u5f15\u5206\u4e3a\u4e3b\u7d22\u5f15\u548c\u8f85\u52a9\u7d22\u5f15\u3002\u4e3b\u7d22\u5f15\u7684\u53f6\u5b50\u8282\u70b9 data \u57df\u8bb0\u5f55\u7740\u5b8c\u6574\u7684\u6570\u636e\u8bb0\u5f55\uff0c\u8fd9\u79cd\u7d22\u5f15\u65b9\u5f0f\u88ab\u79f0\u4e3a\u805a\u7c07\u7d22\u5f15\u3002\u56e0\u4e3a\u65e0\u6cd5\u628a\u6570\u636e\u884c\u5b58\u653e\u5728\u4e24\u4e2a\u4e0d\u540c\u7684\u5730\u65b9\uff0c\u6240\u4ee5\u4e00\u4e2a\u8868\u53ea\u80fd\u6709\u4e00\u4e2a\u805a\u7c07\u7d22\u5f15\u3002<\/p>\n<div align=\"center\"> <img src=\"pics\/4f151e62-6160-47f1-9eff-47b1f4dea4e9.jpg\"\/> <\/div>\n<p><\/p>\n<p>\u8f85\u52a9\u7d22\u5f15\u7684\u53f6\u5b50\u8282\u70b9\u7684 data \u57df\u8bb0\u5f55\u7740\u4e3b\u952e\u7684\u503c\uff0c\u56e0\u6b64\u5728\u4f7f\u7528\u8f85\u52a9\u7d22\u5f15\u8fdb\u884c\u67e5\u627e\u65f6\uff0c\u9700\u8981\u5148\u67e5\u627e\u5230\u4e3b\u952e\u503c\uff0c\u7136\u540e\u518d\u5230\u4e3b\u7d22\u5f15\u4e2d\u8fdb\u884c\u67e5\u627e\u3002<\/p>\n<div align=\"center\"> <img src=\"pics\/40f29839-fd56-4ed0-9353-39dfe6f0bba5.jpg\"\/> <\/div>\n<p><\/p>\n<h3>2. \u54c8\u5e0c\u7d22\u5f15<\/h3>\n<p>\u54c8\u5e0c\u7d22\u5f15\u80fd\u4ee5 O(1) \u65f6\u95f4\u8fdb\u884c\u67e5\u627e\uff0c\u4f46\u662f\u5931\u53bb\u4e86\u6709\u5e8f\u6027\uff1a<\/p>\n<ul>\n<li>\u65e0\u6cd5\u7528\u4e8e\u6392\u5e8f\u4e0e\u5206\u7ec4\uff1b<\/li>\n<li>\u53ea\u652f\u6301\u7cbe\u786e\u67e5\u627e\uff0c\u65e0\u6cd5\u7528\u4e8e\u90e8\u5206\u67e5\u627e\u548c\u8303\u56f4\u67e5\u627e\u3002<\/li>\n<\/ul>\n<p>InnoDB \u5b58\u50a8\u5f15\u64ce\u6709\u4e00\u4e2a\u7279\u6b8a\u7684\u529f\u80fd\u53eb\u201c\u81ea\u9002\u5e94\u54c8\u5e0c\u7d22\u5f15\u201d\uff0c\u5f53\u67d0\u4e2a\u7d22\u5f15\u503c\u88ab\u4f7f\u7528\u7684\u975e\u5e38\u9891\u7e41\u65f6\uff0c\u4f1a\u5728 B+Tree \u7d22\u5f15\u4e4b\u4e0a\u518d\u521b\u5efa\u4e00\u4e2a\u54c8\u5e0c\u7d22\u5f15\uff0c\u8fd9\u6837\u5c31\u8ba9 B+Tree \u7d22\u5f15\u5177\u6709\u54c8\u5e0c\u7d22\u5f15\u7684\u4e00\u4e9b\u4f18\u70b9\uff0c\u6bd4\u5982\u5feb\u901f\u7684\u54c8\u5e0c\u67e5\u627e\u3002<\/p>\n<h3>3. \u5168\u6587\u7d22\u5f15<\/h3>\n<p>MyISAM \u5b58\u50a8\u5f15\u64ce\u652f\u6301\u5168\u6587\u7d22\u5f15\uff0c\u7528\u4e8e\u67e5\u627e\u6587\u672c\u4e2d\u7684\u5173\u952e\u8bcd\uff0c\u800c\u4e0d\u662f\u76f4\u63a5\u6bd4\u8f83\u662f\u5426\u76f8\u7b49\u3002<\/p>\n<p>\u67e5\u627e\u6761\u4ef6\u4f7f\u7528 MATCH AGAINST\uff0c\u800c\u4e0d\u662f\u666e\u901a\u7684 WHERE\u3002<\/p>\n<p>\u5168\u6587\u7d22\u5f15\u4f7f\u7528\u5012\u6392\u7d22\u5f15\u5b9e\u73b0\uff0c\u5b83\u8bb0\u5f55\u7740\u5173\u952e\u8bcd\u5230\u5176\u6240\u5728\u6587\u6863\u7684\u6620\u5c04\u3002<\/p>\n<p>InnoDB \u5b58\u50a8\u5f15\u64ce\u5728 MySQL 5.6.4 \u7248\u672c\u4e2d\u4e5f\u5f00\u59cb\u652f\u6301\u5168\u6587\u7d22\u5f15\u3002<\/p>\n<h3>4. \u7a7a\u95f4\u6570\u636e\u7d22\u5f15<\/h3>\n<p>MyISAM \u5b58\u50a8\u5f15\u64ce\u652f\u6301\u7a7a\u95f4\u6570\u636e\u7d22\u5f15\uff08R-Tree\uff09\uff0c\u53ef\u4ee5\u7528\u4e8e\u5730\u7406\u6570\u636e\u5b58\u50a8\u3002\u7a7a\u95f4\u6570\u636e\u7d22\u5f15\u4f1a\u4ece\u6240\u6709\u7ef4\u5ea6\u6765\u7d22\u5f15\u6570\u636e\uff0c\u53ef\u4ee5\u6709\u6548\u5730\u4f7f\u7528\u4efb\u610f\u7ef4\u5ea6\u6765\u8fdb\u884c\u7ec4\u5408\u67e5\u8be2\u3002<\/p>\n<p>\u5fc5\u987b\u4f7f\u7528 GIS \u76f8\u5173\u7684\u51fd\u6570\u6765\u7ef4\u62a4\u6570\u636e\u3002<\/p>\n<h2>\u7d22\u5f15\u4f18\u5316<\/h2>\n<h3>1. \u72ec\u7acb\u7684\u5217<\/h3>\n<p>\u5728\u8fdb\u884c\u67e5\u8be2\u65f6\uff0c\u7d22\u5f15\u5217\u4e0d\u80fd\u662f\u8868\u8fbe\u5f0f\u7684\u4e00\u90e8\u5206\uff0c\u4e5f\u4e0d\u80fd\u662f\u51fd\u6570\u7684\u53c2\u6570\uff0c\u5426\u5219\u65e0\u6cd5\u4f7f\u7528\u7d22\u5f15\u3002<\/p>\n<p>\u4f8b\u5982\u4e0b\u9762\u7684\u67e5\u8be2\u4e0d\u80fd\u4f7f\u7528 actor_id \u5217\u7684\u7d22\u5f15\uff1a<\/p>\n<pre class=\"brush: sql; title: ; notranslate\" title=\"\">\nSELECT actor_id FROM sakila.actor WHERE actor_id + 1 = 5;\n<\/pre>\n<h3>2. \u591a\u5217\u7d22\u5f15<\/h3>\n<p>\u5728\u9700\u8981\u4f7f\u7528\u591a\u4e2a\u5217\u4f5c\u4e3a\u6761\u4ef6\u8fdb\u884c\u67e5\u8be2\u65f6\uff0c\u4f7f\u7528\u591a\u5217\u7d22\u5f15\u6bd4\u4f7f\u7528\u591a\u4e2a\u5355\u5217\u7d22\u5f15\u6027\u80fd\u66f4\u597d\u3002\u4f8b\u5982\u4e0b\u9762\u7684\u8bed\u53e5\u4e2d\uff0c\u6700\u597d\u628a actor_id \u548c film_id \u8bbe\u7f6e\u4e3a\u591a\u5217\u7d22\u5f15\u3002<\/p>\n<pre class=\"brush: sql; title: ; notranslate\" title=\"\">\nSELECT film_id, actor_ id FROM sakila.film_actor\nWHERE actor_id = 1 AND film_id = 1;\n<\/pre>\n<h3>3. \u7d22\u5f15\u5217\u7684\u987a\u5e8f<\/h3>\n<p>\u8ba9\u9009\u62e9\u6027\u6700\u5f3a\u7684\u7d22\u5f15\u5217\u653e\u5728\u524d\u9762\u3002<\/p>\n<p>\u7d22\u5f15\u7684\u9009\u62e9\u6027\u662f\u6307\uff1a\u4e0d\u91cd\u590d\u7684\u7d22\u5f15\u503c\u548c\u8bb0\u5f55\u603b\u6570\u7684\u6bd4\u503c\u3002\u6700\u5927\u503c\u4e3a 1\uff0c\u6b64\u65f6\u6bcf\u4e2a\u8bb0\u5f55\u90fd\u6709\u552f\u4e00\u7684\u7d22\u5f15\u4e0e\u5176\u5bf9\u5e94\u3002\u9009\u62e9\u6027\u8d8a\u9ad8\uff0c\u67e5\u8be2\u6548\u7387\u4e5f\u8d8a\u9ad8\u3002<\/p>\n<p>\u4f8b\u5982\u4e0b\u9762\u663e\u793a\u7684\u7ed3\u679c\u4e2d customer_id \u7684\u9009\u62e9\u6027\u6bd4 staff_id \u66f4\u9ad8\uff0c\u56e0\u6b64\u6700\u597d\u628a customer_id \u5217\u653e\u5728\u591a\u5217\u7d22\u5f15\u7684\u524d\u9762\u3002<\/p>\n<pre class=\"brush: sql; title: ; notranslate\" title=\"\">\nSELECT COUNT(DISTINCT staff_id)\/COUNT(*) AS staff_id_selectivity,\nCOUNT(DISTINCT customer_id)\/COUNT(*) AS customer_id_selectivity,\nCOUNT(*)\nFROM payment;\n<\/pre>\n<pre class=\"brush: xml; title: ; notranslate\" title=\"\">\n   staff_id_selectivity: 0.0001\ncustomer_id_selectivity: 0.0373\n               COUNT(*): 16049\n<\/pre>\n<h3>4. \u524d\u7f00\u7d22\u5f15<\/h3>\n<p>\u5bf9\u4e8e BLOB\u3001TEXT \u548c VARCHAR \u7c7b\u578b\u7684\u5217\uff0c\u5fc5\u987b\u4f7f\u7528\u524d\u7f00\u7d22\u5f15\uff0c\u53ea\u7d22\u5f15\u5f00\u59cb\u7684\u90e8\u5206\u5b57\u7b26\u3002<\/p>\n<p>\u5bf9\u4e8e\u524d\u7f00\u957f\u5ea6\u7684\u9009\u53d6\u9700\u8981\u6839\u636e\u7d22\u5f15\u9009\u62e9\u6027\u6765\u786e\u5b9a\u3002<\/p>\n<h3>5. \u8986\u76d6\u7d22\u5f15<\/h3>\n<p>\u7d22\u5f15\u5305\u542b\u6240\u6709\u9700\u8981\u67e5\u8be2\u7684\u5b57\u6bb5\u7684\u503c\u3002<\/p>\n<p>\u5177\u6709\u4ee5\u4e0b\u4f18\u70b9\uff1a<\/p>\n<ul>\n<li>\u7d22\u5f15\u901a\u5e38\u8fdc\u5c0f\u4e8e\u6570\u636e\u884c\u7684\u5927\u5c0f\uff0c\u53ea\u8bfb\u53d6\u7d22\u5f15\u80fd\u5927\u5927\u51cf\u5c11\u6570\u636e\u8bbf\u95ee\u91cf\u3002<\/li>\n<li>\u4e00\u4e9b\u5b58\u50a8\u5f15\u64ce\uff08\u4f8b\u5982 MyISAM\uff09\u5728\u5185\u5b58\u4e2d\u53ea\u7f13\u5b58\u7d22\u5f15\uff0c\u800c\u6570\u636e\u4f9d\u8d56\u4e8e\u64cd\u4f5c\u7cfb\u7edf\u6765\u7f13\u5b58\u3002\u56e0\u6b64\uff0c\u53ea\u8bbf\u95ee\u7d22\u5f15\u53ef\u4ee5\u4e0d\u4f7f\u7528\u7cfb\u7edf\u8c03\u7528\uff08\u901a\u5e38\u6bd4\u8f83\u8d39\u65f6\uff09\u3002<\/li>\n<li>\u5bf9\u4e8e InnoDB \u5f15\u64ce\uff0c\u82e5\u8f85\u52a9\u7d22\u5f15\u80fd\u591f\u8986\u76d6\u67e5\u8be2\uff0c\u5219\u65e0\u9700\u8bbf\u95ee\u4e3b\u7d22\u5f15\u3002<\/li>\n<\/ul>\n<h2>\u7d22\u5f15\u7684\u4f18\u70b9<\/h2>\n<ul>\n<li>\u5927\u5927\u51cf\u5c11\u4e86\u670d\u52a1\u5668\u9700\u8981\u626b\u63cf\u7684\u6570\u636e\u884c\u6570\u3002<\/p>\n<\/li>\n<li>\n<p>\u5e2e\u52a9\u670d\u52a1\u5668\u907f\u514d\u8fdb\u884c\u6392\u5e8f\u548c\u5206\u7ec4\uff0c\u4ee5\u53ca\u907f\u514d\u521b\u5efa\u4e34\u65f6\u8868\uff08B+Tree \u7d22\u5f15\u662f\u6709\u5e8f\u7684\uff0c\u53ef\u4ee5\u7528\u4e8e ORDER BY \u548c GROUP BY \u64cd\u4f5c\u3002\u4e34\u65f6\u8868\u4e3b\u8981\u662f\u5728\u6392\u5e8f\u548c\u5206\u7ec4\u8fc7\u7a0b\u4e2d\u521b\u5efa\uff0c\u56e0\u4e3a\u4e0d\u9700\u8981\u6392\u5e8f\u548c\u5206\u7ec4\uff0c\u4e5f\u5c31\u4e0d\u9700\u8981\u521b\u5efa\u4e34\u65f6\u8868\uff09\u3002<\/p>\n<\/li>\n<li>\n<p>\u5c06\u968f\u673a I\/O \u53d8\u4e3a\u987a\u5e8f I\/O\uff08B+Tree \u7d22\u5f15\u662f\u6709\u5e8f\u7684\uff0c\u4f1a\u5c06\u76f8\u90bb\u7684\u6570\u636e\u90fd\u5b58\u50a8\u5728\u4e00\u8d77\uff09\u3002<\/p>\n<\/li>\n<\/ul>\n<h2>\u7d22\u5f15\u7684\u4f7f\u7528\u6761\u4ef6<\/h2>\n<ul>\n<li>\n<p>\u5bf9\u4e8e\u975e\u5e38\u5c0f\u7684\u8868\u3001\u5927\u90e8\u5206\u60c5\u51b5\u4e0b\u7b80\u5355\u7684\u5168\u8868\u626b\u63cf\u6bd4\u5efa\u7acb\u7d22\u5f15\u66f4\u9ad8\u6548\uff1b<\/p>\n<\/li>\n<li>\n<p>\u5bf9\u4e8e\u4e2d\u5230\u5927\u578b\u7684\u8868\uff0c\u7d22\u5f15\u5c31\u975e\u5e38\u6709\u6548\uff1b<\/p>\n<\/li>\n<li>\n<p>\u4f46\u662f\u5bf9\u4e8e\u7279\u5927\u578b\u7684\u8868\uff0c\u5efa\u7acb\u548c\u7ef4\u62a4\u7d22\u5f15\u7684\u4ee3\u4ef7\u5c06\u4f1a\u968f\u4e4b\u589e\u957f\u3002\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0c\u9700\u8981\u7528\u5230\u4e00\u79cd\u6280\u672f\u53ef\u4ee5\u76f4\u63a5\u533a\u5206\u51fa\u9700\u8981\u67e5\u8be2\u7684\u4e00\u7ec4\u6570\u636e\uff0c\u800c\u4e0d\u662f\u4e00\u6761\u8bb0\u5f55\u4e00\u6761\u8bb0\u5f55\u5730\u5339\u914d\uff0c\u4f8b\u5982\u53ef\u4ee5\u4f7f\u7528\u5206\u533a\u6280\u672f\u3002<\/p>\n<\/li>\n<\/ul>\n<h1>\u4e8c\u3001\u67e5\u8be2\u6027\u80fd\u4f18\u5316<\/h1>\n<h2>\u4f7f\u7528 Explain \u8fdb\u884c\u5206\u6790<\/h2>\n<p>Explain \u7528\u6765\u5206\u6790 SELECT \u67e5\u8be2\u8bed\u53e5\uff0c\u5f00\u53d1\u4eba\u5458\u53ef\u4ee5\u901a\u8fc7\u5206\u6790 Explain \u7ed3\u679c\u6765\u4f18\u5316\u67e5\u8be2\u8bed\u53e5\u3002<\/p>\n<p>\u6bd4\u8f83\u91cd\u8981\u7684\u5b57\u6bb5\u6709\uff1a<\/p>\n<ul>\n<li>select_type : \u67e5\u8be2\u7c7b\u578b\uff0c\u6709\u7b80\u5355\u67e5\u8be2\u3001\u8054\u5408\u67e5\u8be2\u3001\u5b50\u67e5\u8be2\u7b49<\/li>\n<li>key : \u4f7f\u7528\u7684\u7d22\u5f15<\/li>\n<li>rows : \u626b\u63cf\u7684\u884c\u6570<\/li>\n<\/ul>\n<h2>\u4f18\u5316\u6570\u636e\u8bbf\u95ee<\/h2>\n<h3>1. \u51cf\u5c11\u8bf7\u6c42\u7684\u6570\u636e\u91cf<\/h3>\n<ul>\n<li>\u53ea\u8fd4\u56de\u5fc5\u8981\u7684\u5217\uff1a\u6700\u597d\u4e0d\u8981\u4f7f\u7528 SELECT * \u8bed\u53e5\u3002<\/li>\n<li>\u53ea\u8fd4\u56de\u5fc5\u8981\u7684\u884c\uff1a\u4f7f\u7528 LIMIT \u8bed\u53e5\u6765\u9650\u5236\u8fd4\u56de\u7684\u6570\u636e\u3002<\/li>\n<li>\u7f13\u5b58\u91cd\u590d\u67e5\u8be2\u7684\u6570\u636e\uff1a\u4f7f\u7528\u7f13\u5b58\u53ef\u4ee5\u907f\u514d\u5728\u6570\u636e\u5e93\u4e2d\u8fdb\u884c\u67e5\u8be2\uff0c\u7279\u522b\u5728\u8981\u67e5\u8be2\u7684\u6570\u636e\u7ecf\u5e38\u88ab\u91cd\u590d\u67e5\u8be2\u65f6\uff0c\u7f13\u5b58\u5e26\u6765\u7684\u67e5\u8be2\u6027\u80fd\u63d0\u5347\u5c06\u4f1a\u662f\u975e\u5e38\u660e\u663e\u7684\u3002<\/li>\n<\/ul>\n<h3>2. \u51cf\u5c11\u670d\u52a1\u5668\u7aef\u626b\u63cf\u7684\u884c\u6570<\/h3>\n<p>\u6700\u6709\u6548\u7684\u65b9\u5f0f\u662f\u4f7f\u7528\u7d22\u5f15\u6765\u8986\u76d6\u67e5\u8be2\u3002<\/p>\n<h2>\u91cd\u6784\u67e5\u8be2\u65b9\u5f0f<\/h2>\n<h3>1. \u5207\u5206\u5927\u67e5\u8be2<\/h3>\n<p>\u4e00\u4e2a\u5927\u67e5\u8be2\u5982\u679c\u4e00\u6b21\u6027\u6267\u884c\u7684\u8bdd\uff0c\u53ef\u80fd\u4e00\u6b21\u9501\u4f4f\u5f88\u591a\u6570\u636e\u3001\u5360\u6ee1\u6574\u4e2a\u4e8b\u52a1\u65e5\u5fd7\u3001\u8017\u5c3d\u7cfb\u7edf\u8d44\u6e90\u3001\u963b\u585e\u5f88\u591a\u5c0f\u7684\u4f46\u91cd\u8981\u7684\u67e5\u8be2\u3002<\/p>\n<pre class=\"brush: sql; title: ; notranslate\" title=\"\">\nDELETE FROM messages WHERE create &amp;lt; DATE_SUB(NOW(), INTERVAL 3 MONTH);\n<\/pre>\n<pre class=\"brush: sql; title: ; notranslate\" title=\"\">\nrows_affected = 0\ndo {\n    rows_affected = do_query(\n    &amp;quot;DELETE FROM messages WHERE create  &amp;lt; DATE_SUB(NOW(), INTERVAL 3 MONTH) LIMIT 10000&amp;quot;)\n} while rows_affected &amp;gt; 0\n<\/pre>\n<h3>2. \u5206\u89e3\u5927\u8fde\u63a5\u67e5\u8be2<\/h3>\n<p>\u5c06\u4e00\u4e2a\u5927\u8fde\u63a5\u67e5\u8be2\u5206\u89e3\u6210\u5bf9\u6bcf\u4e00\u4e2a\u8868\u8fdb\u884c\u4e00\u6b21\u5355\u8868\u67e5\u8be2\uff0c\u7136\u540e\u5728\u5e94\u7528\u7a0b\u5e8f\u4e2d\u8fdb\u884c\u5173\u8054\uff0c\u8fd9\u6837\u505a\u7684\u597d\u5904\u6709\uff1a<\/p>\n<ul>\n<li>\u8ba9\u7f13\u5b58\u66f4\u9ad8\u6548\u3002\u5bf9\u4e8e\u8fde\u63a5\u67e5\u8be2\uff0c\u5982\u679c\u5176\u4e2d\u4e00\u4e2a\u8868\u53d1\u751f\u53d8\u5316\uff0c\u90a3\u4e48\u6574\u4e2a\u67e5\u8be2\u7f13\u5b58\u5c31\u65e0\u6cd5\u4f7f\u7528\u3002\u800c\u5206\u89e3\u540e\u7684\u591a\u4e2a\u67e5\u8be2\uff0c\u5373\u4f7f\u5176\u4e2d\u4e00\u4e2a\u8868\u53d1\u751f\u53d8\u5316\uff0c\u5bf9\u5176\u5b83\u8868\u7684\u67e5\u8be2\u7f13\u5b58\u4f9d\u7136\u53ef\u4ee5\u4f7f\u7528\u3002<\/li>\n<li>\u5206\u89e3\u6210\u591a\u4e2a\u5355\u8868\u67e5\u8be2\uff0c\u8fd9\u4e9b\u5355\u8868\u67e5\u8be2\u7684\u7f13\u5b58\u7ed3\u679c\u66f4\u53ef\u80fd\u88ab\u5176\u5b83\u67e5\u8be2\u4f7f\u7528\u5230\uff0c\u4ece\u800c\u51cf\u5c11\u5197\u4f59\u8bb0\u5f55\u7684\u67e5\u8be2\u3002<\/li>\n<li>\u51cf\u5c11\u9501\u7ade\u4e89\uff1b<\/li>\n<li>\u5728\u5e94\u7528\u5c42\u8fdb\u884c\u8fde\u63a5\uff0c\u53ef\u4ee5\u66f4\u5bb9\u6613\u5bf9\u6570\u636e\u5e93\u8fdb\u884c\u62c6\u5206\uff0c\u4ece\u800c\u66f4\u5bb9\u6613\u505a\u5230\u9ad8\u6027\u80fd\u548c\u53ef\u4f38\u7f29\u3002<\/li>\n<li>\u67e5\u8be2\u672c\u8eab\u6548\u7387\u4e5f\u53ef\u80fd\u4f1a\u6709\u6240\u63d0\u5347\u3002\u4f8b\u5982\u4e0b\u9762\u7684\u4f8b\u5b50\u4e2d\uff0c\u4f7f\u7528 IN() \u4ee3\u66ff\u8fde\u63a5\u67e5\u8be2\uff0c\u53ef\u4ee5\u8ba9 MySQL \u6309\u7167 ID \u987a\u5e8f\u8fdb\u884c\u67e5\u8be2\uff0c\u8fd9\u53ef\u80fd\u6bd4\u968f\u673a\u7684\u8fde\u63a5\u8981\u66f4\u9ad8\u6548\u3002<\/li>\n<\/ul>\n<pre class=\"brush: sql; title: ; notranslate\" title=\"\">\nSELECT * FROM tab\nJOIN tag_post ON tag_post.tag_id=tag.id\nJOIN post ON tag_post.post_id=post.id\nWHERE tag.tag=&amp;#039;mysql&amp;#039;;\n<\/pre>\n<pre class=\"brush: sql; title: ; notranslate\" title=\"\">\nSELECT * FROM tag WHERE tag=&amp;#039;mysql&amp;#039;;\nSELECT * FROM tag_post WHERE tag_id=1234;\nSELECT * FROM post WHERE post.id IN (123,456,567,9098,8904);\n<\/pre>\n<h1>\u4e09\u3001\u5b58\u50a8\u5f15\u64ce<\/h1>\n<h2>InnoDB<\/h2>\n<p>\u662f MySQL \u9ed8\u8ba4\u7684\u4e8b\u52a1\u578b\u5b58\u50a8\u5f15\u64ce\uff0c\u53ea\u6709\u5728\u9700\u8981\u5b83\u4e0d\u652f\u6301\u7684\u7279\u6027\u65f6\uff0c\u624d\u8003\u8651\u4f7f\u7528\u5176\u5b83\u5b58\u50a8\u5f15\u64ce\u3002<\/p>\n<p>\u5b9e\u73b0\u4e86\u56db\u4e2a\u6807\u51c6\u7684\u9694\u79bb\u7ea7\u522b\uff0c\u9ed8\u8ba4\u7ea7\u522b\u662f\u53ef\u91cd\u590d\u8bfb\uff08REPEATABLE READ\uff09\u3002\u5728\u53ef\u91cd\u590d\u8bfb\u9694\u79bb\u7ea7\u522b\u4e0b\uff0c\u901a\u8fc7\u591a\u7248\u672c\u5e76\u53d1\u63a7\u5236\uff08MVCC\uff09+ \u95f4\u9699\u9501\uff08Next-Key Locking\uff09\u9632\u6b62\u5e7b\u5f71\u8bfb\u3002<\/p>\n<p>\u4e3b\u7d22\u5f15\u662f\u805a\u7c07\u7d22\u5f15\uff0c\u5728\u7d22\u5f15\u4e2d\u4fdd\u5b58\u4e86\u6570\u636e\uff0c\u4ece\u800c\u907f\u514d\u76f4\u63a5\u8bfb\u53d6\u78c1\u76d8\uff0c\u56e0\u6b64\u5bf9\u67e5\u8be2\u6027\u80fd\u6709\u5f88\u5927\u7684\u63d0\u5347\u3002<\/p>\n<p>\u5185\u90e8\u505a\u4e86\u5f88\u591a\u4f18\u5316\uff0c\u5305\u62ec\u4ece\u78c1\u76d8\u8bfb\u53d6\u6570\u636e\u65f6\u91c7\u7528\u7684\u53ef\u9884\u6d4b\u6027\u8bfb\u3001\u80fd\u591f\u52a0\u5feb\u8bfb\u64cd\u4f5c\u5e76\u4e14\u81ea\u52a8\u521b\u5efa\u7684\u81ea\u9002\u5e94\u54c8\u5e0c\u7d22\u5f15\u3001\u80fd\u591f\u52a0\u901f\u63d2\u5165\u64cd\u4f5c\u7684\u63d2\u5165\u7f13\u51b2\u533a\u7b49\u3002<\/p>\n<p>\u652f\u6301\u771f\u6b63\u7684\u5728\u7ebf\u70ed\u5907\u4efd\u3002\u5176\u5b83\u5b58\u50a8\u5f15\u64ce\u4e0d\u652f\u6301\u5728\u7ebf\u70ed\u5907\u4efd\uff0c\u8981\u83b7\u53d6\u4e00\u81f4\u6027\u89c6\u56fe\u9700\u8981\u505c\u6b62\u5bf9\u6240\u6709\u8868\u7684\u5199\u5165\uff0c\u800c\u5728\u8bfb\u5199\u6df7\u5408\u573a\u666f\u4e2d\uff0c\u505c\u6b62\u5199\u5165\u53ef\u80fd\u4e5f\u610f\u5473\u7740\u505c\u6b62\u8bfb\u53d6\u3002<\/p>\n<h2>MyISAM<\/h2>\n<p>\u8bbe\u8ba1\u7b80\u5355\uff0c\u6570\u636e\u4ee5\u7d27\u5bc6\u683c\u5f0f\u5b58\u50a8\u3002\u5bf9\u4e8e\u53ea\u8bfb\u6570\u636e\uff0c\u6216\u8005\u8868\u6bd4\u8f83\u5c0f\u3001\u53ef\u4ee5\u5bb9\u5fcd\u4fee\u590d\u64cd\u4f5c\uff0c\u5219\u4f9d\u7136\u53ef\u4ee5\u4f7f\u7528\u5b83\u3002<\/p>\n<p>\u63d0\u4f9b\u4e86\u5927\u91cf\u7684\u7279\u6027\uff0c\u5305\u62ec\u538b\u7f29\u8868\u3001\u7a7a\u95f4\u6570\u636e\u7d22\u5f15\u7b49\u3002<\/p>\n<p>\u4e0d\u652f\u6301\u4e8b\u52a1\u3002<\/p>\n<p>\u4e0d\u652f\u6301\u884c\u7ea7\u9501\uff0c\u53ea\u80fd\u5bf9\u6574\u5f20\u8868\u52a0\u9501\uff0c\u8bfb\u53d6\u65f6\u4f1a\u5bf9\u9700\u8981\u8bfb\u5230\u7684\u6240\u6709\u8868\u52a0\u5171\u4eab\u9501\uff0c\u5199\u5165\u65f6\u5219\u5bf9\u8868\u52a0\u6392\u5b83\u9501\u3002\u4f46\u5728\u8868\u6709\u8bfb\u53d6\u64cd\u4f5c\u7684\u540c\u65f6\uff0c\u4e5f\u53ef\u4ee5\u5f80\u8868\u4e2d\u63d2\u5165\u65b0\u7684\u8bb0\u5f55\uff0c\u8fd9\u88ab\u79f0\u4e3a\u5e76\u53d1\u63d2\u5165\uff08CONCURRENT INSERT\uff09\u3002<\/p>\n<p>\u53ef\u4ee5\u624b\u5de5\u6216\u8005\u81ea\u52a8\u6267\u884c\u68c0\u67e5\u548c\u4fee\u590d\u64cd\u4f5c\uff0c\u4f46\u662f\u548c\u4e8b\u52a1\u6062\u590d\u4ee5\u53ca\u5d29\u6e83\u6062\u590d\u4e0d\u540c\uff0c\u53ef\u80fd\u5bfc\u81f4\u4e00\u4e9b\u6570\u636e\u4e22\u5931\uff0c\u800c\u4e14\u4fee\u590d\u64cd\u4f5c\u662f\u975e\u5e38\u6162\u7684\u3002<\/p>\n<p>\u5982\u679c\u6307\u5b9a\u4e86 DELAY_KEY_WRITE \u9009\u9879\uff0c\u5728\u6bcf\u6b21\u4fee\u6539\u6267\u884c\u5b8c\u6210\u65f6\uff0c\u4e0d\u4f1a\u7acb\u5373\u5c06\u4fee\u6539\u7684\u7d22\u5f15\u6570\u636e\u5199\u5165\u78c1\u76d8\uff0c\u800c\u662f\u4f1a\u5199\u5230\u5185\u5b58\u4e2d\u7684\u952e\u7f13\u51b2\u533a\uff0c\u53ea\u6709\u5728\u6e05\u7406\u952e\u7f13\u51b2\u533a\u6216\u8005\u5173\u95ed\u8868\u7684\u65f6\u5019\u624d\u4f1a\u5c06\u5bf9\u5e94\u7684\u7d22\u5f15\u5757\u5199\u5165\u78c1\u76d8\u3002\u8fd9\u79cd\u65b9\u5f0f\u53ef\u4ee5\u6781\u5927\u7684\u63d0\u5347\u5199\u5165\u6027\u80fd\uff0c\u4f46\u662f\u5728\u6570\u636e\u5e93\u6216\u8005\u4e3b\u673a\u5d29\u6e83\u65f6\u4f1a\u9020\u6210\u7d22\u5f15\u635f\u574f\uff0c\u9700\u8981\u6267\u884c\u4fee\u590d\u64cd\u4f5c\u3002<\/p>\n<h2>\u6bd4\u8f83<\/h2>\n<ul>\n<li>\u4e8b\u52a1\uff1aInnoDB \u662f\u4e8b\u52a1\u578b\u7684\uff0c\u53ef\u4ee5\u4f7f\u7528 Commit \u548c Rollback \u8bed\u53e5\u3002<\/p>\n<\/li>\n<li>\n<p>\u5e76\u53d1\uff1aMyISAM \u53ea\u652f\u6301\u8868\u7ea7\u9501\uff0c\u800c InnoDB \u8fd8\u652f\u6301\u884c\u7ea7\u9501\u3002<\/p>\n<\/li>\n<li>\n<p>\u5916\u952e\uff1aInnoDB \u652f\u6301\u5916\u952e\u3002<\/p>\n<\/li>\n<li>\n<p>\u5907\u4efd\uff1aInnoDB \u652f\u6301\u5728\u7ebf\u70ed\u5907\u4efd\u3002<\/p>\n<\/li>\n<li>\n<p>\u5d29\u6e83\u6062\u590d\uff1aMyISAM \u5d29\u6e83\u540e\u53d1\u751f\u635f\u574f\u7684\u6982\u7387\u6bd4 InnoDB \u9ad8\u5f88\u591a\uff0c\u800c\u4e14\u6062\u590d\u7684\u901f\u5ea6\u4e5f\u66f4\u6162\u3002<\/p>\n<\/li>\n<li>\n<p>\u5176\u5b83\u7279\u6027\uff1aMyISAM \u652f\u6301\u538b\u7f29\u8868\u548c\u7a7a\u95f4\u6570\u636e\u7d22\u5f15\u3002<\/p>\n<\/li>\n<\/ul>\n<h1>\u56db\u3001\u6570\u636e\u7c7b\u578b<\/h1>\n<h2>\u6574\u578b<\/h2>\n<p>TINYINT, SMALLINT, MEDIUMINT, INT, BIGINT \u5206\u522b\u4f7f\u7528 8, 16, 24, 32, 64 \u4f4d\u5b58\u50a8\u7a7a\u95f4\uff0c\u4e00\u822c\u60c5\u51b5\u4e0b\u8d8a\u5c0f\u7684\u5217\u8d8a\u597d\u3002<\/p>\n<p>INT(11) \u4e2d\u7684\u6570\u5b57\u53ea\u662f\u89c4\u5b9a\u4e86\u4ea4\u4e92\u5de5\u5177\u663e\u793a\u5b57\u7b26\u7684\u4e2a\u6570\uff0c\u5bf9\u4e8e\u5b58\u50a8\u548c\u8ba1\u7b97\u6765\u8bf4\u662f\u6ca1\u6709\u610f\u4e49\u7684\u3002<\/p>\n<h2>\u6d6e\u70b9\u6570<\/h2>\n<p>FLOAT \u548c DOUBLE \u4e3a\u6d6e\u70b9\u7c7b\u578b\uff0cDECIMAL \u4e3a\u9ad8\u7cbe\u5ea6\u5c0f\u6570\u7c7b\u578b\u3002CPU \u539f\u751f\u652f\u6301\u6d6e\u70b9\u8fd0\u7b97\uff0c\u4f46\u662f\u4e0d\u652f\u6301 DECIMAl \u7c7b\u578b\u7684\u8ba1\u7b97\uff0c\u56e0\u6b64 DECIMAL \u7684\u8ba1\u7b97\u6bd4\u6d6e\u70b9\u7c7b\u578b\u9700\u8981\u66f4\u9ad8\u7684\u4ee3\u4ef7\u3002<\/p>\n<p>FLOAT\u3001DOUBLE \u548c DECIMAL \u90fd\u53ef\u4ee5\u6307\u5b9a\u5217\u5bbd\uff0c\u4f8b\u5982 DECIMAL(18, 9) \u8868\u793a\u603b\u5171 18 \u4f4d\uff0c\u53d6 9 \u4f4d\u5b58\u50a8\u5c0f\u6570\u90e8\u5206\uff0c\u5269\u4e0b 9 \u4f4d\u5b58\u50a8\u6574\u6570\u90e8\u5206\u3002<\/p>\n<h2>\u5b57\u7b26\u4e32<\/h2>\n<p>\u4e3b\u8981\u6709 CHAR \u548c VARCHAR \u4e24\u79cd\u7c7b\u578b\uff0c\u4e00\u79cd\u662f\u5b9a\u957f\u7684\uff0c\u4e00\u79cd\u662f\u53d8\u957f\u7684\u3002<\/p>\n<p>VARCHAR \u8fd9\u79cd\u53d8\u957f\u7c7b\u578b\u80fd\u591f\u8282\u7701\u7a7a\u95f4\uff0c\u56e0\u4e3a\u53ea\u9700\u8981\u5b58\u50a8\u5fc5\u8981\u7684\u5185\u5bb9\u3002\u4f46\u662f\u5728\u6267\u884c UPDATE \u65f6\u53ef\u80fd\u4f1a\u4f7f\u884c\u53d8\u5f97\u6bd4\u539f\u6765\u957f\uff0c\u5f53\u8d85\u51fa\u4e00\u4e2a\u9875\u6240\u80fd\u5bb9\u7eb3\u7684\u5927\u5c0f\u65f6\uff0c\u5c31\u8981\u6267\u884c\u989d\u5916\u7684\u64cd\u4f5c\u3002MyISAM \u4f1a\u5c06\u884c\u62c6\u6210\u4e0d\u540c\u7684\u7247\u6bb5\u5b58\u50a8\uff0c\u800c InnoDB \u5219\u9700\u8981\u5206\u88c2\u9875\u6765\u4f7f\u884c\u653e\u8fdb\u9875\u5185\u3002<\/p>\n<p>\u5728\u8fdb\u884c\u5b58\u50a8\u548c\u68c0\u7d22\u65f6\uff0c\u4f1a\u4fdd\u7559 VARCHAR \u672b\u5c3e\u7684\u7a7a\u683c\uff0c\u800c\u4f1a\u5220\u9664 CHAR \u672b\u5c3e\u7684\u7a7a\u683c\u3002<\/p>\n<h2>\u65f6\u95f4\u548c\u65e5\u671f<\/h2>\n<p>MySQL \u63d0\u4f9b\u4e86\u4e24\u79cd\u76f8\u4f3c\u7684\u65e5\u671f\u65f6\u95f4\u7c7b\u578b\uff1aDATETIME \u548c TIMESTAMP\u3002<\/p>\n<h3>1. DATETIME<\/h3>\n<p>\u80fd\u591f\u4fdd\u5b58\u4ece 1001 \u5e74\u5230 9999 \u5e74\u7684\u65e5\u671f\u548c\u65f6\u95f4\uff0c\u7cbe\u5ea6\u4e3a\u79d2\uff0c\u4f7f\u7528 8 \u5b57\u8282\u7684\u5b58\u50a8\u7a7a\u95f4\u3002<\/p>\n<p>\u5b83\u4e0e\u65f6\u533a\u65e0\u5173\u3002<\/p>\n<p>\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0cMySQL \u4ee5\u4e00\u79cd\u53ef\u6392\u5e8f\u7684\u3001\u65e0\u6b67\u4e49\u7684\u683c\u5f0f\u663e\u793a DATETIME \u503c\uff0c\u4f8b\u5982\u201c2008-01-16 22:37:08\u201d\uff0c\u8fd9\u662f ANSI \u6807\u51c6\u5b9a\u4e49\u7684\u65e5\u671f\u548c\u65f6\u95f4\u8868\u793a\u65b9\u6cd5\u3002<\/p>\n<h3>2. TIMESTAMP<\/h3>\n<p>\u548c UNIX \u65f6\u95f4\u6233\u76f8\u540c\uff0c\u4fdd\u5b58\u4ece 1970 \u5e74 1 \u6708 1 \u65e5\u5348\u591c\uff08\u683c\u6797\u5a01\u6cbb\u65f6\u95f4\uff09\u4ee5\u6765\u7684\u79d2\u6570\uff0c\u4f7f\u7528 4 \u4e2a\u5b57\u8282\uff0c\u53ea\u80fd\u8868\u793a\u4ece 1970 \u5e74\u5230 2038 \u5e74\u3002<\/p>\n<p>\u5b83\u548c\u65f6\u533a\u6709\u5173\uff0c\u4e5f\u5c31\u662f\u8bf4\u4e00\u4e2a\u65f6\u95f4\u6233\u5728\u4e0d\u540c\u7684\u65f6\u533a\u6240\u4ee3\u8868\u7684\u5177\u4f53\u65f6\u95f4\u662f\u4e0d\u540c\u7684\u3002<\/p>\n<p>MySQL \u63d0\u4f9b\u4e86 FROM_UNIXTIME() \u51fd\u6570\u628a UNIX \u65f6\u95f4\u6233\u8f6c\u6362\u4e3a\u65e5\u671f\uff0c\u5e76\u63d0\u4f9b\u4e86 UNIX_TIMESTAMP() \u51fd\u6570\u628a\u65e5\u671f\u8f6c\u6362\u4e3a UNIX \u65f6\u95f4\u6233\u3002<\/p>\n<p>\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0c\u5982\u679c\u63d2\u5165\u65f6\u6ca1\u6709\u6307\u5b9a TIMESTAMP \u5217\u7684\u503c\uff0c\u4f1a\u5c06\u8fd9\u4e2a\u503c\u8bbe\u7f6e\u4e3a\u5f53\u524d\u65f6\u95f4\u3002<\/p>\n<p>\u5e94\u8be5\u5c3d\u91cf\u4f7f\u7528 TIMESTAMP\uff0c\u56e0\u4e3a\u5b83\u6bd4 DATETIME \u7a7a\u95f4\u6548\u7387\u66f4\u9ad8\u3002<\/p>\n<h1>\u4e94\u3001\u5207\u5206<\/h1>\n<h2>\u6c34\u5e73\u5207\u5206<\/h2>\n<p>\u6c34\u5e73\u5207\u5206\u53c8\u79f0\u4e3a Sharding\uff0c\u5b83\u662f\u5c06\u540c\u4e00\u4e2a\u8868\u4e2d\u7684\u8bb0\u5f55\u62c6\u5206\u5230\u591a\u4e2a\u7ed3\u6784\u76f8\u540c\u7684\u8868\u4e2d\u3002<\/p>\n<p>\u5f53\u4e00\u4e2a\u8868\u7684\u6570\u636e\u4e0d\u65ad\u589e\u591a\u65f6\uff0cSharding \u662f\u5fc5\u7136\u7684\u9009\u62e9\uff0c\u5b83\u53ef\u4ee5\u5c06\u6570\u636e\u5206\u5e03\u5230\u96c6\u7fa4\u7684\u4e0d\u540c\u8282\u70b9\u4e0a\uff0c\u4ece\u800c\u7f13\u5b58\u5355\u4e2a\u6570\u636e\u5e93\u7684\u538b\u529b\u3002<\/p>\n<div align=\"center\"> <img src=\"pics\/63c2909f-0c5f-496f-9fe5-ee9176b31aba.jpg\"\/> <\/div>\n<p><\/p>\n<h2>\u5782\u76f4\u5207\u5206<\/h2>\n<p>\u5782\u76f4\u5207\u5206\u662f\u5c06\u4e00\u5f20\u8868\u6309\u5217\u5207\u5206\u6210\u591a\u4e2a\u8868\uff0c\u901a\u5e38\u662f\u6309\u7167\u5217\u7684\u5173\u7cfb\u5bc6\u96c6\u7a0b\u5ea6\u8fdb\u884c\u5207\u5206\uff0c\u4e5f\u53ef\u4ee5\u5229\u7528\u5782\u76f4\u5207\u5206\u5c06\u7ecf\u5e38\u88ab\u4f7f\u7528\u7684\u5217\u548c\u4e0d\u7ecf\u5e38\u88ab\u4f7f\u7528\u7684\u5217\u5207\u5206\u5230\u4e0d\u540c\u7684\u8868\u4e2d\u3002<\/p>\n<p>\u5728\u6570\u636e\u5e93\u7684\u5c42\u9762\u4f7f\u7528\u5782\u76f4\u5207\u5206\u5c06\u6309\u6570\u636e\u5e93\u4e2d\u8868\u7684\u5bc6\u96c6\u7a0b\u5ea6\u90e8\u7f72\u5230\u4e0d\u540c\u7684\u5e93\u4e2d\uff0c\u4f8b\u5982\u5c06\u539f\u6765\u7684\u7535\u5546\u6570\u636e\u5e93\u5782\u76f4\u5207\u5206\u6210\u5546\u54c1\u6570\u636e\u5e93\u3001\u7528\u6237\u6570\u636e\u5e93\u7b49\u3002<\/p>\n<div align=\"center\"> <img src=\"pics\/e130e5b8-b19a-4f1e-b860-223040525cf6.jpg\"\/> <\/div>\n<p><\/p>\n<h2>Sharding \u7b56\u7565<\/h2>\n<ul>\n<li>\u54c8\u5e0c\u53d6\u6a21\uff1ahash(key) % N\uff1b<\/li>\n<li>\u8303\u56f4\uff1a\u53ef\u4ee5\u662f ID \u8303\u56f4\u4e5f\u53ef\u4ee5\u662f\u65f6\u95f4\u8303\u56f4\uff1b<\/li>\n<li>\u6620\u5c04\u8868\uff1a\u4f7f\u7528\u5355\u72ec\u7684\u4e00\u4e2a\u6570\u636e\u5e93\u6765\u5b58\u50a8\u6620\u5c04\u5173\u7cfb\u3002<\/li>\n<\/ul>\n<h2>Sharding \u5b58\u5728\u7684\u95ee\u9898<\/h2>\n<h3>1. \u4e8b\u52a1\u95ee\u9898<\/h3>\n<p>\u4f7f\u7528\u5206\u5e03\u5f0f\u4e8b\u52a1\u6765\u89e3\u51b3\uff0c\u6bd4\u5982 XA \u63a5\u53e3\u3002<\/p>\n<h3>2. \u8fde\u63a5<\/h3>\n<p>\u53ef\u4ee5\u5c06\u539f\u6765\u7684\u8fde\u63a5\u5206\u89e3\u6210\u591a\u4e2a\u5355\u8868\u67e5\u8be2\uff0c\u7136\u540e\u5728\u7528\u6237\u7a0b\u5e8f\u4e2d\u8fdb\u884c\u8fde\u63a5\u3002<\/p>\n<h3>3. ID \u552f\u4e00\u6027<\/h3>\n<ul>\n<li>\u4f7f\u7528\u5168\u5c40\u552f\u4e00 ID\uff08GUID\uff09<\/li>\n<li>\u4e3a\u6bcf\u4e2a\u5206\u7247\u6307\u5b9a\u4e00\u4e2a ID \u8303\u56f4<\/li>\n<li>\u5206\u5e03\u5f0f ID \u751f\u6210\u5668 (\u5982 Twitter \u7684 Snowflake \u7b97\u6cd5)<\/li>\n<\/ul>\n<h1>\u516d\u3001\u590d\u5236<\/h1>\n<h2>\u4e3b\u4ece\u590d\u5236<\/h2>\n<p>\u4e3b\u8981\u6d89\u53ca\u4e09\u4e2a\u7ebf\u7a0b\uff1abinlog \u7ebf\u7a0b\u3001I\/O \u7ebf\u7a0b\u548c SQL \u7ebf\u7a0b\u3002<\/p>\n<ul>\n<li><strong>binlog \u7ebf\u7a0b<\/strong> \uff1a\u8d1f\u8d23\u5c06\u4e3b\u670d\u52a1\u5668\u4e0a\u7684\u6570\u636e\u66f4\u6539\u5199\u5165\u4e8c\u8fdb\u5236\u65e5\u5fd7\uff08Binary log\uff09\u4e2d\u3002<\/li>\n<li><strong>I\/O \u7ebf\u7a0b<\/strong> \uff1a\u8d1f\u8d23\u4ece\u4e3b\u670d\u52a1\u5668\u4e0a\u8bfb\u53d6\u4e8c\u8fdb\u5236\u65e5\u5fd7\uff0c\u5e76\u5199\u5165\u4ece\u670d\u52a1\u5668\u7684\u91cd\u653e\u65e5\u5fd7\uff08Replay log\uff09\u4e2d\u3002<\/li>\n<li><strong>SQL \u7ebf\u7a0b<\/strong> \uff1a\u8d1f\u8d23\u8bfb\u53d6\u91cd\u653e\u65e5\u5fd7\u5e76\u91cd\u653e\u5176\u4e2d\u7684 SQL \u8bed\u53e5\u3002<\/li>\n<\/ul>\n<div align=\"center\"> <img src=\"pics\/master-slave.png\"\/> <\/div>\n<p><\/p>\n<h2>\u8bfb\u5199\u5206\u79bb<\/h2>\n<p>\u4e3b\u670d\u52a1\u5668\u5904\u7406\u5199\u64cd\u4f5c\u4ee5\u53ca\u5b9e\u65f6\u6027\u8981\u6c42\u6bd4\u8f83\u9ad8\u7684\u8bfb\u64cd\u4f5c\uff0c\u800c\u4ece\u670d\u52a1\u5668\u5904\u7406\u8bfb\u64cd\u4f5c\u3002<\/p>\n<p>\u8bfb\u5199\u5206\u79bb\u80fd\u63d0\u9ad8\u6027\u80fd\u7684\u539f\u56e0\u5728\u4e8e\uff1a<\/p>\n<ul>\n<li>\u4e3b\u4ece\u670d\u52a1\u5668\u8d1f\u8d23\u5404\u81ea\u7684\u8bfb\u548c\u5199\uff0c\u6781\u5927\u7a0b\u5ea6\u7f13\u89e3\u4e86\u9501\u7684\u4e89\u7528\uff1b<\/li>\n<li>\u4ece\u670d\u52a1\u5668\u53ef\u4ee5\u4f7f\u7528 MyISAM\uff0c\u63d0\u5347\u67e5\u8be2\u6027\u80fd\u4ee5\u53ca\u8282\u7ea6\u7cfb\u7edf\u5f00\u9500\uff1b<\/li>\n<li>\u589e\u52a0\u5197\u4f59\uff0c\u63d0\u9ad8\u53ef\u7528\u6027\u3002<\/li>\n<\/ul>\n<p>\u8bfb\u5199\u5206\u79bb\u5e38\u7528\u4ee3\u7406\u65b9\u5f0f\u6765\u5b9e\u73b0\uff0c\u4ee3\u7406\u670d\u52a1\u5668\u63a5\u6536\u5e94\u7528\u5c42\u4f20\u6765\u7684\u8bfb\u5199\u8bf7\u6c42\uff0c\u7136\u540e\u51b3\u5b9a\u8f6c\u53d1\u5230\u54ea\u4e2a\u670d\u52a1\u5668\u3002<\/p>\n<div align=\"center\"> <img src=\"pics\/master-slave-proxy.png\"\/> <\/div>\n<p><\/p>\n<h1>\u53c2\u8003\u8d44\u6599<\/h1>\n<ul>\n<li>BaronScbwartz, PeterZaitsev, VadimTkacbenko, \u7b49. \u9ad8\u6027\u80fd MySQL[M]. \u7535\u5b50\u5de5\u4e1a\u51fa\u7248\u793e, 2013.<\/li>\n<li>\u59dc\u627f\u5c27. MySQL \u6280\u672f\u5185\u5e55: InnoDB \u5b58\u50a8\u5f15\u64ce [M]. \u673a\u68b0\u5de5\u4e1a\u51fa\u7248\u793e, 2011.<\/li>\n<li><a href=\"https:\/\/www.jfox.info\/20-tiao-mysql-xing-nen-you-hua-de-zui-jia-jing-yan.html\" target=\"_blank\" rel=\"noopener\">20+ \u6761 MySQL \u6027\u80fd\u4f18\u5316\u7684\u6700\u4f73\u7ecf\u9a8c<\/a><\/li>\n<li><a href=\"http:\/\/blog.720ui.com\/2017\/mysql_core_09_multi_db_table2\/\" title=\"\u670d\u52a1\u7aef\u6307\u5357 \u6570\u636e\u5b58\u50a8\u7bc7 | MySQL\uff0809\uff09 \u5206\u5e93\u4e0e\u5206\u8868\u5e26\u6765\u7684\u5206\u5e03\u5f0f\u56f0\u5883\u4e0e\u5e94\u5bf9\u4e4b\u7b56\" target=\"_blank\" rel=\"noopener\">\u670d\u52a1\u7aef\u6307\u5357 \u6570\u636e\u5b58\u50a8\u7bc7 | MySQL\uff0809\uff09 \u5206\u5e93\u4e0e\u5206\u8868\u5e26\u6765\u7684\u5206\u5e03\u5f0f\u56f0\u5883\u4e0e\u5e94\u5bf9\u4e4b\u7b56<\/a><\/li>\n<li><a href=\"https:\/\/stackoverflow.com\/questions\/788829\/how-to-create-unique-row-id-in-sharded-databases\" target=\"_blank\" rel=\"noopener\">How to create unique row ID in sharded databases?<\/a><\/li>\n<li><a href=\"http:\/\/geekswithblogs.net\/shaunxu\/archive\/2012\/01\/07\/sql-azure-federation-ndash-introduction.aspx\" title=\"Title of this entry.\" target=\"_blank\" rel=\"noopener\">SQL Azure Federation \u2013 Introduction<\/a><\/li>\n<li><a href=\"http:\/\/blog.codinglabs.org\/articles\/theory-of-mysql-index.html\" target=\"_blank\" rel=\"noopener\">MySQL \u7d22\u5f15\u80cc\u540e\u7684\u6570\u636e\u7ed3\u6784\u53ca\u7b97\u6cd5\u539f\u7406<\/a><\/li>\n<li><a href=\"https:\/\/segmentfault.com\/a\/1190000008131735\" target=\"_blank\" rel=\"noopener\">MySQL \u6027\u80fd\u4f18\u5316\u795e\u5668 Explain \u4f7f\u7528\u5206\u6790<\/a><\/li>\n<li><a href=\"https:\/\/medium.com\/@jeeyoungk\/how-sharding-works-b4dec46b3f6\" target=\"_blank\" rel=\"noopener\">How Sharding Works<\/a><\/li>\n<li><a href=\"https:\/\/tech.meituan.com\/dianping_order_db_sharding.html\" target=\"_blank\" rel=\"noopener\">\u5927\u4f17\u70b9\u8bc4\u8ba2\u5355\u7cfb\u7edf\u5206\u5e93\u5206\u8868\u5b9e\u8df5<\/a><\/li>\n<li><a href=\"https:\/\/zh.wikipedia.org\/wiki\/B%2B%E6%A0%91\" target=\"_blank\" rel=\"noopener\">B + \u6811<\/a><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>\u53c2\u8003 \u4e00\u3001\u7d22\u5f15 B+ Tree \u539f\u7406 1. \u6570\u636e\u7ed3\u6784 B Tree \u6307\u7684\u662f Balance Tree\uff0c\u4e5f\u5c31\u662f\u5e73<a href=\"https:\/\/www.ccagml.com\/?p=272\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">MySQL\u57fa\u7840\u77e5\u8bc6<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[18,22],"tags":[],"_links":{"self":[{"href":"https:\/\/www.ccagml.com\/index.php?rest_route=\/wp\/v2\/posts\/272"}],"collection":[{"href":"https:\/\/www.ccagml.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ccagml.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ccagml.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ccagml.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=272"}],"version-history":[{"count":4,"href":"https:\/\/www.ccagml.com\/index.php?rest_route=\/wp\/v2\/posts\/272\/revisions"}],"predecessor-version":[{"id":288,"href":"https:\/\/www.ccagml.com\/index.php?rest_route=\/wp\/v2\/posts\/272\/revisions\/288"}],"wp:attachment":[{"href":"https:\/\/www.ccagml.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=272"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ccagml.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=272"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ccagml.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=272"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}