{"id":160159,"date":"2024-11-03T20:46:22","date_gmt":"2024-11-03T12:46:22","guid":{"rendered":"https:\/\/server.hk\/cnblog\/160159\/"},"modified":"2024-11-03T20:46:23","modified_gmt":"2024-11-03T12:46:23","slug":"oceanbase-%e6%95%99%e7%a8%8b%ef%bc%9aoceanbase-least","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/160159\/","title":{"rendered":"OceanBase \u6559\u7a0b\uff1aOceanBase LEAST"},"content":{"rendered":"<h1 id=\"oceanbase-%e6%95%99%e7%a8%8b%ef%bc%9aoceanbase-least-oYwlHSuTAC\">OceanBase \u6559\u7a0b\uff1aOceanBase LEAST<\/h1>\n<p>\u5728\u7576\u4eca\u7684\u6578\u64da\u5eab\u6280\u8853\u4e2d\uff0cOceanBase \u4f5c\u70ba\u4e00\u500b\u9ad8\u6027\u80fd\u7684\u5206\u4f48\u5f0f\u6578\u64da\u5eab\u7cfb\u7d71\uff0c\u8d8a\u4f86\u8d8a\u53d7\u5230\u958b\u767c\u8005\u548c\u4f01\u696d\u7684\u9752\u775e\u3002\u5b83\u7531\u963f\u91cc\u5df4\u5df4\u96c6\u5718\u958b\u767c\uff0c\u65e8\u5728\u652f\u6301\u5927\u898f\u6a21\u7684\u5728\u7dda\u4ea4\u6613\u8655\u7406\uff08OLTP\uff09\u548c\u5728\u7dda\u5206\u6790\u8655\u7406\uff08OLAP\uff09\u3002\u5728\u9019\u7bc7\u6587\u7ae0\u4e2d\uff0c\u6211\u5011\u5c07\u6df1\u5165\u63a2\u8a0e OceanBase \u7684 LEAST\uff08Least Recently Used\uff09\u7de9\u5b58\u7b56\u7565\uff0c\u4e26\u63d0\u4f9b\u4e00\u4e9b\u5be6\u7528\u7684\u793a\u4f8b\u548c\u4ee3\u78bc\u7247\u6bb5\uff0c\u5e6b\u52a9\u8b80\u8005\u66f4\u597d\u5730\u7406\u89e3\u548c\u61c9\u7528\u9019\u4e00\u6280\u8853\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af-oceanbase-least-%e7%b7%a9%e5%ad%98%e7%ad%96%e7%95%a5%ef%bc%9f-oYwlHSuTAC\">\u4ec0\u9ebc\u662f OceanBase LEAST \u7de9\u5b58\u7b56\u7565\uff1f<\/h2>\n<p>LEAST \u7de9\u5b58\u7b56\u7565\u662f\u4e00\u7a2e\u5e38\u898b\u7684\u7de9\u5b58\u6dd8\u6c70\u7b97\u6cd5\uff0c\u4e3b\u8981\u7528\u65bc\u7ba1\u7406\u6709\u9650\u7684\u7de9\u5b58\u7a7a\u9593\u3002\u5176\u57fa\u672c\u539f\u5247\u662f\u7576\u7de9\u5b58\u6eff\u6642\uff0c\u6dd8\u6c70\u6700\u8fd1\u6700\u5c11\u4f7f\u7528\u7684\u6578\u64da\uff0c\u4ee5\u4fbf\u70ba\u65b0\u6578\u64da\u9a30\u51fa\u7a7a\u9593\u3002\u5728 OceanBase \u4e2d\uff0cLEAST \u7b56\u7565\u88ab\u7528\u4f86\u512a\u5316\u67e5\u8a62\u6027\u80fd\uff0c\u7279\u5225\u662f\u5728\u9ad8\u4e26\u767c\u7684\u74b0\u5883\u4e2d\u3002<\/p>\n<h2 id=\"oceanbase-%e7%9a%84%e6%9e%b6%e6%a7%8b-oYwlHSuTAC\">OceanBase \u7684\u67b6\u69cb<\/h2>\n<p>\u5728\u6df1\u5165 LEAST \u7b56\u7565\u4e4b\u524d\uff0c\u4e86\u89e3 OceanBase \u7684\u57fa\u672c\u67b6\u69cb\u662f\u975e\u5e38\u91cd\u8981\u7684\u3002OceanBase \u7684\u67b6\u69cb\u4e3b\u8981\u7531\u4ee5\u4e0b\u5e7e\u500b\u90e8\u5206\u7d44\u6210\uff1a<\/p>\n<ul>\n<li><strong>\u5b58\u5132\u5c64\uff1a<\/strong>\u8ca0\u8cac\u6578\u64da\u7684\u6301\u4e45\u5316\u548c\u5b58\u5132\u3002<\/li>\n<li><strong>\u8a08\u7b97\u5c64\uff1a<\/strong>\u8ca0\u8cac\u6578\u64da\u7684\u67e5\u8a62\u548c\u8655\u7406\u3002<\/li>\n<li><strong>\u7ba1\u7406\u5c64\uff1a<\/strong>\u8ca0\u8cac\u7cfb\u7d71\u7684\u76e3\u63a7\u548c\u7ba1\u7406\u3002<\/li>\n<\/ul>\n<p>\u9019\u7a2e\u5206\u5c64\u67b6\u69cb\u4f7f\u5f97 OceanBase \u80fd\u5920\u5728\u9ad8\u53ef\u7528\u6027\u548c\u9ad8\u6027\u80fd\u4e4b\u9593\u53d6\u5f97\u826f\u597d\u7684\u5e73\u8861\u3002<\/p>\n<h2 id=\"%e5%a6%82%e4%bd%95%e5%af%a6%e7%8f%be-least-%e7%b7%a9%e5%ad%98%e7%ad%96%e7%95%a5-oYwlHSuTAC\">\u5982\u4f55\u5be6\u73fe LEAST \u7de9\u5b58\u7b56\u7565<\/h2>\n<p>\u5728 OceanBase \u4e2d\u5be6\u73fe LEAST \u7de9\u5b58\u7b56\u7565\u7684\u904e\u7a0b\u53ef\u4ee5\u5206\u70ba\u4ee5\u4e0b\u5e7e\u500b\u6b65\u9a5f\uff1a<\/p>\n<h3 id=\"1-%e8%a8%ad%e5%ae%9a%e7%b7%a9%e5%ad%98%e5%a4%a7%e5%b0%8f-oYwlHSuTAC\">1. \u8a2d\u5b9a\u7de9\u5b58\u5927\u5c0f<\/h3>\n<p>\u9996\u5148\uff0c\u60a8\u9700\u8981\u6839\u64da\u61c9\u7528\u7684\u9700\u6c42\u8a2d\u5b9a\u7de9\u5b58\u7684\u5927\u5c0f\u3002\u9019\u53ef\u4ee5\u901a\u904e\u914d\u7f6e\u6587\u4ef6\u9032\u884c\u8a2d\u7f6e\uff0c\u4f8b\u5982\uff1a<\/p>\n<pre><code>\n# \u8a2d\u5b9a\u7de9\u5b58\u5927\u5c0f\u70ba 1GB\ncache_size = 1G\n<\/code><\/pre>\n<h3 id=\"2-%e5%af%a6%e7%8f%be-least-%e7%ad%96%e7%95%a5-oYwlHSuTAC\">2. \u5be6\u73fe LEAST \u7b56\u7565<\/h3>\n<p>\u63a5\u4e0b\u4f86\uff0c\u60a8\u9700\u8981\u5728\u6578\u64da\u5eab\u4e2d\u5be6\u73fe LEAST \u7b56\u7565\u3002\u9019\u901a\u5e38\u6d89\u53ca\u5230\u5c0d\u6578\u64da\u7684\u8a2a\u554f\u8a08\u6578\u548c\u6642\u9593\u6233\u7684\u7ba1\u7406\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u7c21\u55ae\u7684\u793a\u4f8b\uff1a<\/p>\n<pre><code>\nCREATE TABLE cache (\n    id INT PRIMARY KEY,\n    data VARCHAR(255),\n    last_accessed TIMESTAMP DEFAULT CURRENT_TIMESTAMP\n);\n\n-- \u63d2\u5165\u6578\u64da\nINSERT INTO cache (id, data) VALUES (1, 'data1');\nINSERT INTO cache (id, data) VALUES (2, 'data2');\n\n-- \u66f4\u65b0\u8a2a\u554f\u6642\u9593\nUPDATE cache SET last_accessed = CURRENT_TIMESTAMP WHERE id = 1;\n\n-- \u67e5\u8a62\u6700\u8fd1\u6700\u5c11\u4f7f\u7528\u7684\u6578\u64da\nSELECT * FROM cache ORDER BY last_accessed ASC LIMIT 1;\n<\/code><\/pre>\n<h3 id=\"3-%e5%ae%9a%e6%9c%9f%e6%b8%85%e7%90%86%e7%b7%a9%e5%ad%98-oYwlHSuTAC\">3. \u5b9a\u671f\u6e05\u7406\u7de9\u5b58<\/h3>\n<p>\u6700\u5f8c\uff0c\u60a8\u9700\u8981\u5b9a\u671f\u6e05\u7406\u7de9\u5b58\uff0c\u4ee5\u78ba\u4fdd\u7cfb\u7d71\u7684\u6027\u80fd\u3002\u9019\u53ef\u4ee5\u901a\u904e\u5b9a\u6642\u4efb\u52d9\u4f86\u5be6\u73fe\uff0c\u4f8b\u5982\uff1a<\/p>\n<pre><code>\nDELETE FROM cache WHERE last_accessed &lt; NOW() - INTERVAL 1 HOUR;\n<\/code><\/pre>\n<h2 id=\"%e7%b5%90%e8%ab%96-oYwlHSuTAC\">\u7d50\u8ad6<\/h2>\n<p>OceanBase \u7684 LEAST \u7de9\u5b58\u7b56\u7565\u662f\u4e00\u7a2e\u6709\u6548\u7684\u6578\u64da\u7ba1\u7406\u65b9\u6cd5\uff0c\u80fd\u5920\u986f\u8457\u63d0\u9ad8\u7cfb\u7d71\u7684\u67e5\u8a62\u6027\u80fd\u3002\u901a\u904e\u5408\u7406\u914d\u7f6e\u7de9\u5b58\u5927\u5c0f\u3001\u5be6\u73fe LEAST \u7b56\u7565\u4ee5\u53ca\u5b9a\u671f\u6e05\u7406\u7de9\u5b58\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u5728\u9ad8\u4e26\u767c\u7684\u74b0\u5883\u4e2d\u4fdd\u6301\u7cfb\u7d71\u7684\u7a69\u5b9a\u6027\u548c\u9ad8\u6548\u6027\u3002<\/p>\n<p>\u5982\u679c\u60a8\u5c0d\u65bc\u5982\u4f55\u5728\u9999\u6e2f\u4f7f\u7528 <a href=\"https:\/\/server.hk\">VPS<\/a> \u4f86\u90e8\u7f72 OceanBase \u6709\u8208\u8da3\uff0c\u6216\u60f3\u4e86\u89e3\u66f4\u591a\u95dc\u65bc <a href=\"https:\/\/server.hk\">\u9999\u6e2f\u4f3a\u670d\u5668<\/a> \u7684\u8cc7\u8a0a\uff0c\u6b61\u8fce\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u4ee5\u7372\u53d6\u66f4\u591a\u8a73\u7d30\u8cc7\u6599\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5b66\u4e60OceanBase LEAST\u7684\u57fa\u7840\u77e5\u8bc6\uff0c\u638c\u63e1\u9ad8\u6548\u6570\u636e\u5b58\u50a8\u4e0e\u7ba1\u7406\u6280\u5de7\uff0c\u63d0\u5347\u6570\u636e\u5e93\u6027\u80fd\u4e0e\u5e94\u7528\u80fd\u529b\u3002<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-160159","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/160159","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=160159"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/160159\/revisions"}],"predecessor-version":[{"id":160160,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/160159\/revisions\/160160"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=160159"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=160159"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=160159"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}