{"id":255,"date":"2024-10-08T13:46:16","date_gmt":"2024-10-08T05:46:16","guid":{"rendered":"http:\/\/www.bigqq.com\/?p=255"},"modified":"2025-02-21T13:38:09","modified_gmt":"2025-02-21T05:38:09","slug":"pg-%e6%95%b0%e6%8d%ae%e5%ba%93wal%e6%96%87%e4%bb%b6","status":"publish","type":"post","link":"http:\/\/www.bigqq.com\/?p=255","title":{"rendered":"PG \u6570\u636e\u5e93WAL\u6587\u4ef6"},"content":{"rendered":"\n<p>\u83b7\u53d6\u6d41\u540c\u6b65\u4fe1\u606f<\/p>\n\n\n\n<p><strong>select<\/strong> * <strong>from<\/strong> <strong><em>pg_stat_replication<\/em><\/strong><\/p>\n\n\n\n<p>\u83b7\u53d6\u6d41\u540c\u6b65\u5ef6\u8fdf\u6570\u636e\u91cfMB<\/p>\n\n\n\n<p><span style=\"color: rgb(128, 0, 0); font-weight: bold; font-family: Consolas; font-size: 10pt; text-wrap: nowrap; background-color: var(--ast-global-color-5);\">SELECT<\/span><div style=\"padding: 0px 0px 0px 2px;\"><div style=\"color: rgb(0, 0, 0); font-family: Consolas; font-size: 10pt; text-wrap: nowrap;\"><p style=\"margin:0;\">        pg_wal_lsn_diff(<span style=\"color: rgb(255, 55, 55); font-style: italic; font-weight: bold; text-decoration-line: underline; text-decoration-style: solid;\">A<\/span> .c1, <span style=\"color: rgb(255, 55, 55); font-style: italic; font-weight: bold; text-decoration-line: underline; text-decoration-style: solid;\">replay_lsn<\/span>) \/(<span style=\"color:#0000ff;\">1024<\/span> * <span style=\"color:#0000ff;\">1024<\/span>) <span style=\"color:#800000;font-weight:bold;\">AS<\/span> <span style=\"color:#006464;font-style:italic;\">slave_latency_MB<\/span><\/p><p style=\"margin:0;\">        <span style=\"color:#800000;font-weight:bold;\">FROM<\/span><\/p><p style=\"margin:0;\">        \t<span style=\"color: rgb(255, 55, 55); font-style: italic; font-weight: bold; text-decoration-line: underline; text-decoration-style: solid;\">pg_stat_replication<\/span>,<\/p><p style=\"margin:0;\">        \tpg_current_wal_lsn() <span style=\"color:#800000;font-weight:bold;\">AS<\/span> A(c1)<\/p><p style=\"margin:0;\">        <span style=\"color:#800000;font-weight:bold;\">ORDER<\/span> <span style=\"color:#800000;font-weight:bold;\">BY<\/span><\/p><p style=\"margin:0;\">        \t<span style=\"color:#006464;font-style:italic;\">slave_latency_MB<\/span><\/p><p style=\"margin:0;\">        <span style=\"color:#800000;font-weight:bold;\">LIMIT<\/span> <span style=\"color:#0000ff;\">1<\/span><span style=\"color:#ff0000;\">;<\/span><\/p><\/div><\/div><\/p>\n\n\n\n<p>\u6839\u636eWAL\u5e8f\u5217\u53f7\uff0c\u83b7\u53d6\u5bf9\u5e94\u7684WAL\u6587\u4ef6<\/p>\n\n\n\n<p><strong>select<\/strong> pg_walfile_name(<strong>&#8216;3E\/7A13B0D0&#8217;<\/strong>);<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>LSN:3FB\/AE61A1A0\n3FB\uff1a\u4ee3\u8868wal\u6587\u4ef6\u7684\u7b2c\u4e8c\u90e8\u5206\nAE\uff1a\u4ee3\u8868wal\u6587\u4ef6\u7684\u6700\u540e\u4e24\u4f4d\n61A1A0\uff1a\u4ee3\u8868\u504f\u79fb\u91cf\n\n00000001000003FB000000AE\nwal\u6587\u4ef6\u753124\u4e2a\u5b57\u7b26\uff0c\u4e09\u90e8\u5206\u7ec4\u6210\uff0c\u6bcf\u90e8\u5206\u75318\u4e2a\u5b57\u7b26\u7ec4\u6210\uff0c\u4ee3\u8868\u542b\u4e49\u5982\u4e0b\n00000001\uff1a\u4ee3\u8868\u6570\u636e\u5e93\u8fd0\u884c\u7684\u65f6\u95f4\u8f74\uff0c\u5982\u679c\u6062\u590d\u8fc7\u6570\u636e\u5e93\uff08\u4e3b\u5907\u5207\u6362\uff09\u8fd9\u4e2a\u503c\u4f1a\u589e\u5927\n000003FB\uff1a\u5bf9LSN\u7684\u7b2c\u4e8c\u90e8\u5206\u5bf9\u5e94\n000000AE\uff1a\u4ee3\u8868walfile\u6587\u4ef6\u7684\u6700\u540e\u4e24\u4f4d<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>\u83b7\u53d6\u6d41\u540c\u6b65\u4fe1\u606f select * fro [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","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":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center 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