{"id":20642,"date":"2024-01-02T05:12:25","date_gmt":"2024-01-02T05:12:25","guid":{"rendered":"https:\/\/server.hk\/blog\/20642\/"},"modified":"2024-11-14T10:39:29","modified_gmt":"2024-11-14T02:39:29","slug":"postgresql-command-set-transaction","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/20642\/","title":{"rendered":"PostgreSQL \u547d\u4ee4: SET TRANSACTION"},"content":{"rendered":"<h1 id=\"postgresql-command-set-transaction-KTecWARKbl\">PostgreSQL \u547d\u4ee4: SET TRANSACTION<\/h1>\n<p>PostgreSQL \u662f\u4e00\u500b\u529f\u80fd\u5f37\u5927\u7684\u958b\u6e90\u95dc\u806f\u5f0f\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\uff0c\u63d0\u4f9b\u591a\u7a2e\u529f\u80fd\u548c\u80fd\u529b\u3002<code>SET TRANSACTION<\/code> \u662f PostgreSQL \u4e2d\u4e00\u500b\u91cd\u8981\u7684\u547d\u4ee4\uff0c\u5b83\u5141\u8a31\u7528\u6236\u63a7\u5236\u4e8b\u52d9\u7684\u5404\u500b\u65b9\u9762\u3002<\/p>\n<h2 id=\"understanding-transactions-KTecWARKbl\">\u4e86\u89e3\u4e8b\u52d9<\/h2>\n<p>\u5728 PostgreSQL \u4e2d\uff0c\u4e8b\u52d9\u662f\u4e00\u7cfb\u5217\u88ab\u8996\u70ba\u4e00\u500b\u5de5\u4f5c\u55ae\u5143\u7684\u6578\u64da\u5eab\u64cd\u4f5c\u3002\u4e8b\u52d9\u78ba\u4fdd\u5176\u5167\u90e8\u7684\u6240\u6709\u64cd\u4f5c\u8981\u9ebc\u5168\u90e8\u6210\u529f\u5b8c\u6210\uff0c\u8981\u9ebc\u5728\u51fa\u73fe\u932f\u8aa4\u6642\u5168\u90e8\u56de\u6efe\u3002\u9019\u6a23\u53ef\u4ee5\u4fdd\u8b49\u6578\u64da\u7684\u5b8c\u6574\u6027\u548c\u4e00\u81f4\u6027\u3002<\/p>\n<p>PostgreSQL \u4e2d\u7684\u4e8b\u52d9\u9075\u5faa ACID\uff08\u539f\u5b50\u6027\u3001\u4e00\u81f4\u6027\u3001\u9694\u96e2\u6027\u3001\u6301\u4e45\u6027\uff09\u5c6c\u6027\uff0c\u9019\u78ba\u4fdd\u6578\u64da\u5eab\u5373\u4f7f\u5728\u51fa\u73fe\u6545\u969c\u6642\uff0c\u4e5f\u80fd\u4fdd\u6301\u4e00\u81f4\u7684\u72c0\u614b\u3002<\/p>\n<h2 id=\"the-set-transaction-command-KTecWARKbl\">SET TRANSACTION \u547d\u4ee4<\/h2>\n<p>PostgreSQL \u4e2d\u7684 <code>SET TRANSACTION<\/code> \u547d\u4ee4\u5141\u8a31\u7528\u6236\u901a\u904e\u8a2d\u7f6e\u5404\u7a2e\u4e8b\u52d9\u7279\u6027\u4f86\u4fee\u6539\u4e8b\u52d9\u7684\u884c\u70ba\u3002\u9019\u4e9b\u7279\u6027\u5305\u62ec\u9694\u96e2\u7d1a\u5225\u3001\u53ea\u8b80\u6a21\u5f0f\u3001\u53ef\u5ef6\u9072\u6a21\u5f0f\u548c\u4e8b\u52d9\u8a2a\u554f\u6a21\u5f0f\u3002<\/p>\n<h3 id=\"isolation-level-KTecWARKbl\">\u9694\u96e2\u7d1a\u5225<\/h3>\n<p>\u9694\u96e2\u7d1a\u5225\u6c7a\u5b9a\u4e86\u4e26\u767c\u4e8b\u52d9\u4e4b\u9593\u7684\u76f8\u4e92\u4f5c\u7528\u3002PostgreSQL \u652f\u63f4\u56db\u7a2e\u9694\u96e2\u7d1a\u5225\uff1a<\/p>\n<ul>\n<li><strong>\u8b80\u672a\u63d0\u4ea4\uff08Read Uncommitted\uff09\uff1a<\/strong>\u5141\u8a31\u9ad2\u8b80\uff0c\u5373\u4e00\u500b\u4e8b\u52d9\u53ef\u4ee5\u770b\u5230\u5176\u4ed6\u4e8b\u52d9\u672a\u63d0\u4ea4\u7684\u66f4\u6539\u3002<\/li>\n<li><strong>\u8b80\u63d0\u4ea4\uff08Read Committed\uff09\uff1a<\/strong>\u78ba\u4fdd\u4e8b\u52d9\u53ea\u80fd\u770b\u5230\u5176\u4ed6\u4e8b\u52d9\u63d0\u4ea4\u7684\u66f4\u6539\u3002<\/li>\n<li><strong>\u53ef\u91cd\u8907\u8b80\uff08Repeatable Read\uff09\uff1a<\/strong>\u4fdd\u8b49\u4e8b\u52d9\u770b\u5230\u7684\u662f\u6578\u64da\u5eab\u7684\u4e00\u81f4\u5feb\u7167\uff0c\u5373\u4f7f\u5176\u4ed6\u4e8b\u52d9\u4fee\u6539\u4e86\u6578\u64da\u3002<\/li>\n<li><strong>\u53ef\u5e8f\u5217\u5316\uff08Serializable\uff09\uff1a<\/strong>\u63d0\u4f9b\u6700\u9ad8\u7d1a\u5225\u7684\u9694\u96e2\uff0c\u78ba\u4fdd\u4e26\u767c\u4e8b\u52d9\u7684\u884c\u70ba\u5c31\u50cf\u5b83\u5011\u662f\u6309\u9806\u5e8f\u57f7\u884c\u7684\u4e00\u6a23\u3002<\/li>\n<\/ul>\n<p>\u53ef\u4ee5\u4f7f\u7528 <code>SET TRANSACTION ISOLATION LEVEL<\/code> \u547d\u4ee4\u4f86\u8a2d\u7f6e\u9694\u96e2\u7d1a\u5225\u3002<\/p>\n<h3 id=\"read-only-mode-KTecWARKbl\">\u53ea\u8b80\u6a21\u5f0f<\/h3>\n<p>\u53ea\u8b80\u6a21\u5f0f\u6307\u5b9a\u4e8b\u52d9\u662f\u5426\u53ef\u4ee5\u4fee\u6539\u6578\u64da\u5eab\u3002\u9ed8\u8a8d\u60c5\u6cc1\u4e0b\uff0c\u4e8b\u52d9\u8655\u65bc\u8b80\u5beb\u6a21\u5f0f\uff0c\u5141\u8a31\u9032\u884c\u8b80\u5beb\u64cd\u4f5c\u3002\u7136\u800c\uff0c\u4f60\u53ef\u4ee5\u4f7f\u7528 <code>SET TRANSACTION READ ONLY<\/code> \u547d\u4ee4\u5c07\u4e8b\u52d9\u8a2d\u7f6e\u70ba\u53ea\u8b80\u6a21\u5f0f\u3002<\/p>\n<h3 id=\"deferrable-mode-KTecWARKbl\">\u53ef\u5ef6\u9072\u6a21\u5f0f<\/h3>\n<p>\u53ef\u5ef6\u9072\u6a21\u5f0f\u5141\u8a31\u4e8b\u52d9\u5c07\u7d04\u675f\u6aa2\u67e5\u63a8\u9072\u5230\u4e8b\u52d9\u7d50\u675f\u6642\u3002\u7576\u4f60\u9700\u8981\u5728\u4e8b\u52d9\u904e\u7a0b\u4e2d\u66ab\u6642\u9055\u53cd\u7d04\u675f\u6642\uff0c\u9019\u500b\u6a21\u5f0f\u6703\u5f88\u6709\u7528\u3002\u53ef\u4ee5\u4f7f\u7528 <code>SET TRANSACTION DEFERRABLE<\/code> \u547d\u4ee4\u555f\u7528\u53ef\u5ef6\u9072\u6a21\u5f0f\u3002<\/p>\n<h3 id=\"transaction-access-mode-KTecWARKbl\">\u4e8b\u52d9\u8a2a\u554f\u6a21\u5f0f<\/h3>\n<p>\u4e8b\u52d9\u8a2a\u554f\u6a21\u5f0f\u6c7a\u5b9a\u4e86\u4e8b\u52d9\u662f\u5426\u53ef\u4ee5\u770b\u5230\u5176\u4ed6\u4e8b\u52d9\u6240\u505a\u7684\u66f4\u6539\u3002\u9ed8\u8a8d\u60c5\u6cc1\u4e0b\uff0c\u4e8b\u52d9\u8655\u65bc<em>\u8b80\u5beb<\/em>\u6a21\u5f0f\uff0c\u5141\u8a31\u5b83\u5011\u770b\u5230\u5176\u4ed6\u4e8b\u52d9\u7684\u66f4\u6539\u3002\u7136\u800c\uff0c\u4f60\u53ef\u4ee5\u4f7f\u7528 <code>SET TRANSACTION READ ONLY<\/code> \u547d\u4ee4\u5c07\u4e8b\u52d9\u8a2d\u7f6e\u70ba<em>\u53ea\u8b80<\/em>\u6a21\u5f0f\uff0c\u9019\u6a23\u53ef\u4ee5\u9632\u6b62\u5b83\u770b\u5230\u5176\u4ed6\u4e8b\u52d9\u7684\u66f4\u6539\u3002<\/p>\n<h2 id=\"examples-KTecWARKbl\">\u7bc4\u4f8b<\/h2>\n<p>\u8b93\u6211\u5011\u4f86\u770b\u770b\u4e00\u4e9b\u7bc4\u4f8b\uff0c\u4f86\u7406\u89e3 <code>SET TRANSACTION<\/code> \u547d\u4ee4\u5982\u4f55\u904b\u4f5c\uff1a<\/p>\n<pre><code>SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;\r\n<\/code><\/pre>\n<p>\u9019\u5c07\u628a\u4e8b\u52d9\u7684\u9694\u96e2\u7d1a\u5225\u8a2d\u7f6e\u70ba<em>\u53ef\u91cd\u8907\u8b80<\/em>\u3002<\/p>\n<pre><code>SET TRANSACTION READ ONLY;\r\n<\/code><\/pre>\n<p>\u9019\u5c07\u628a\u4e8b\u52d9\u8a2d\u7f6e\u70ba\u53ea\u8b80\u6a21\u5f0f\uff0c\u9632\u6b62\u5c0d\u6578\u64da\u5eab\u9032\u884c\u4efb\u4f55\u4fee\u6539\u3002<\/p>\n<pre><code>SET TRANSACTION DEFERRABLE;\r\n<\/code><\/pre>\n<p>\u9019\u5c07\u70ba\u4e8b\u52d9\u555f\u7528\u53ef\u5ef6\u9072\u6a21\u5f0f\uff0c\u5141\u8a31\u7d04\u675f\u9055\u53cd\u5ef6\u9072\u5230\u4e8b\u52d9\u7d50\u675f\u6642\u8655\u7406\u3002<\/p>\n<h2 id=\"summary-KTecWARKbl\">\u7e3d\u7d50<\/h2>\n<p>PostgreSQL \u4e2d\u7684 <code>SET TRANSACTION<\/code> \u547d\u4ee4\u5141\u8a31\u7528\u6236\u63a7\u5236\u4e8b\u52d9\u7684\u5404\u500b\u65b9\u9762\uff0c\u4f8b\u5982\u9694\u96e2\u7d1a\u5225\u3001\u53ea\u8b80\u6a21\u5f0f\u3001\u53ef\u5ef6\u9072\u6a21\u5f0f\u548c\u4e8b\u52d9\u8a2a\u554f\u6a21\u5f0f\u3002\u7406\u89e3\u4e26\u4f7f\u7528\u9019\u4e9b\u4e8b\u52d9\u7279\u6027\u53ef\u4ee5\u5e6b\u52a9\u512a\u5316 PostgreSQL \u6578\u64da\u5eab\u7684\u6027\u80fd\u548c\u884c\u70ba\u3002<\/p>\n<p>\u5982\u9700\u4e86\u89e3\u66f4\u591a\u6709\u95dc PostgreSQL \u53ca\u5176\u529f\u80fd\u7684\u8cc7\u8a0a\uff0c\u8acb\u8003\u616e\u63a2\u7d22 <a href=\"https:\/\/server.hk\">Server.HK<\/a>\uff0c\u9019\u662f\u4e00\u5bb6\u9818\u5148\u7684 VPS \u8a17\u7ba1\u516c\u53f8\uff0c\u63d0\u4f9b\u53ef\u9760\u4e14\u9ad8\u6548\u80fd\u7684\u8a17\u7ba1\u89e3\u6c7a\u65b9\u6848\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>PostgreSQL \u547d\u4ee4: S&#46;&#46;&#46;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4924],"tags":[],"class_list":["post-20642","post","type-post","status-publish","format-standard","hentry","category-setup-tutorials"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/20642","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"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=20642"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/20642\/revisions"}],"predecessor-version":[{"id":24370,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/20642\/revisions\/24370"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=20642"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=20642"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=20642"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}