{"Entry":{"collection":"guc","key":"timezone_abbreviations","name":"timezone_abbreviations","aliases":[],"metadata":{"baseline":false,"boot_human":"Not specified","boot_val":null,"category":"Client Connection Defaults / Locale and Formatting","category_zh":"","changed_in":["9.1"],"changes":[{"documentation_changed":false,"fields":{},"from":"8.1","status":"added","to":"8.2"},{"documentation_changed":true,"fields":{},"from":"8.4","status":"changed","to":"9.0"},{"documentation_changed":false,"fields":{"boot_val":{"from":"UNKNOWN","to":null}},"from":"9.0","status":"changed","to":"9.1"},{"documentation_changed":true,"fields":{},"from":"9.3","status":"changed","to":"9.4"},{"documentation_changed":true,"fields":{},"from":"17","status":"changed","to":"18"}],"content_hash":"15684a6439e04a89b90fc5b063210b2cdc87e7f09a46c9fb7ecd1dda0708e0d3","context":"","default_changed_in":["9.1"],"default_history":[{"from":"9.0","to":"9.0","value":"UNKNOWN"},{"from":"9.1","to":"19","value":"Not specified"}],"editorial":{"advice":{"olap":"Pin timezone_abbreviations for export, reporting, and reproducible analytical jobs; prefer explicit SQL formatting when a file or API has a durable schema.","oltp":"Treat timezone_abbreviations as an application contract, not a performance knob. Standardize it per role or connection pool and keep wire formats explicit where clients parse text.","small":"Keep the upstream or locale-derived value unless a client requires another one. A smaller server gains no capacity from changing timezone_abbreviations."},"mechanism":["timezone_abbreviations selects a file of time zone abbreviations. The selected set changes accepted datetime input tokens and can make the same abbreviation resolve differently by region.","timezone_abbreviations is a USER-context setting. An authorized role can change it for a session, while ALTER ROLE or ALTER DATABASE can establish a default for future sessions.","It changes representation, parsing, or locale behavior at the client boundary rather than physical storage. Coordinate it with the other locale and formatting settings and with driver-native binary or typed protocols."],"pitfalls":["Changing timezone_abbreviations in one session and assuming role defaults, database defaults, or other pooled sessions changed with it.","Assuming a presentation setting changes stored values or server-side type semantics.","Changing a role or database default without testing text-parsing clients, exports, and pooled sessions.","Accepting a region-specific abbreviation set that gives familiar tokens a different UTC offset."],"references":[{"title":"PostgreSQL 19 Beta 4: timezone_abbreviations","url":"https://www.postgresql.org/docs/19/runtime-config-client.html#GUC-TIMEZONE-ABBREVIATIONS"},{"title":"PostgreSQL 19 release notes","url":"https://www.postgresql.org/docs/19/release-19.html"}],"related":["DateStyle","IntervalStyle","TimeZone","lc_time","log_timezone"],"summary":"timezone_abbreviations is the PostgreSQL setting that selects a file of time zone abbreviations."},"enumvals":[],"first_version":"8.2","group":"Client Connection Defaults","group_slug":"client","imported_at":"2026-09-27T17:57:32.165039+08:00","intro_commit":{},"key":"timezone_abbreviations","last_version":"20","max_val":"","min_val":"","name":"timezone_abbreviations","position":414,"present_in":["8.2","8.3","8.4","9.0","9.1","9.2","9.3","9.4","9.5","9.6","10","11","12","13","14","15","16","17","18","19","20"],"short_desc":"Sets the collection of additional time zone abbreviations that will be accepted by the server for datetime input (beyond any abbreviations defined by the current TimeZone setting).","short_desc_zh":"","source_rev":"english-manuals:b638bb800f32a404011e08160885695a8e1c1883ea5e0e2f5d796a55c6d62eeb","unit":"","vartype":"string"}},"Definition":{"Collection":"guc","Key":"timezone_abbreviations","SourceDatabase":"center","Version":"18","SourceTable":"guc","SourceKey":"timezone_abbreviations","SourceRevision":"english-manuals:b638bb800f32a404011e08160885695a8e1c1883ea5e0e2f5d796a55c6d62eeb","Facts":{"boot_val":null,"category":"Client Connection Defaults / Locale and Formatting","context":"user","description":"Sets the collection of additional time zone abbreviations that will be accepted by the server for datetime input (beyond any abbreviations defined by the current TimeZone setting). The default is 'Default', which is a collection that works in most of the world; there are also 'Australia' and 'India', and other collections can be defined for a particular installation. See Section B.4 for more information.","doc":{"anchor":"GUC-TIMEZONE-ABBREVIATIONS","file":"runtime-config-client.html","lang":"en","sha256":"6be6cc70f29eca4695dc43b2b2b94c75b7e0eaaa2c00273d7a98488917a7edb7","slug":"18"},"documented":true,"enumvals":null,"extra_desc":null,"lang":"en","max_val":null,"metadata_version":"18","min_val":null,"name":"timezone_abbreviations","short_desc":"Selects a file of time zone abbreviations.","source":"pg-settings-source-snapshot","unit":null,"vartype":"string"},"ManualEvidence":{"doc":{"anchor":"GUC-TIMEZONE-ABBREVIATIONS","file":"runtime-config-client.html","lang":"en","sha256":"6be6cc70f29eca4695dc43b2b2b94c75b7e0eaaa2c00273d7a98488917a7edb7","slug":"18"}},"MeasuredEvidence":{"metadata_version":"18"}},"Text":{"Collection":"guc","Key":"timezone_abbreviations","SourceDatabase":"pgweb","Version":"18","Locale":"zh-Hans","Title":"timezone_abbreviations","Summary":"","BodyHTML":"\u003cp\u003e设置服务器在日期时间输入中接受的额外时区缩写集合（除当前\u003ccode\u003eTimeZone\u003c/code\u003e设置所定义的缩写之外）。默认值为\u003ccode\u003e\u0026#39;Default\u0026#39;\u003c/code\u003e，这个集合在全世界大多数地方都能工作。也还有\u003ccode\u003e\u0026#39;Australia\u0026#39;\u003c/code\u003e和\u003ccode\u003e\u0026#39;India\u0026#39;\u003c/code\u003e，以及可能为一种特定安装定义的其他集合。详见\u003ca href=\"/docs/18/datetime-config-files.html\" rel=\"nofollow\"\u003e第 B.4 节\u003c/a\u003e。\u003c/p\u003e","SourceRevision":"2026-09-11@29c86d9","ContentHash":"6e372a97bacf231b7697c56b812ed971d1e5494e7273fe4abc332b24bb2aa9bd","Payload":{"carried_from":"","carry_reason":"","doc_html":"\u003cp\u003e设置服务器在日期时间输入中接受的额外时区缩写集合（除当前\u003ccode class=\"varname\"\u003eTimeZone\u003c/code\u003e设置所定义的缩写之外）。默认值为\u003ccode class=\"literal\"\u003e'Default'\u003c/code\u003e，这个集合在全世界大多数地方都能工作。也还有\u003ccode class=\"literal\"\u003e'Australia'\u003c/code\u003e和\u003ccode class=\"literal\"\u003e'India'\u003c/code\u003e，以及可能为一种特定安装定义的其他集合。详见\u003ca href=\"/docs/18/datetime-config-files.html\" title=\"B.4. 日期/时间配置文件\"\u003e第 B.4 节\u003c/a\u003e。\u003c/p\u003e","doc_same_as":""}},"RequestedLocale":"zh-Hans","Fallback":false,"Versions":["10","11","12","13","14","15","16","17","18","19","20","8.2","8.3","8.4","9.0","9.1","9.2","9.3","9.4","9.5","9.6"],"Locales":["en","zh-Hans"],"Signatures":null,"Spellings":null,"SQLState":null,"Evidence":null}