{"Entry":{"collection":"guc","key":"autovacuum_vacuum_max_threshold","name":"autovacuum_vacuum_max_threshold","aliases":[],"metadata":{"baseline":false,"boot_human":"Not specified","boot_val":null,"category":"Vacuuming / Automatic Vacuuming","category_zh":"","changed_in":[],"changes":[{"documentation_changed":false,"fields":{},"from":"17","status":"added","to":"18"}],"content_hash":"a7ca44ba261ccc4e3cddf9d8177b447e0d3b3df2c22d331144d21a6ff67aa78a","context":"","default_changed_in":[],"default_history":[{"from":"18","to":"19","value":"100000000"}],"editorial":{"advice":{"olap":"Run explicit ANALYZE/VACUUM after bulk loads instead of waiting only for proportional triggers; plan freezing and visibility-map advancement separately for append-only partitions.","oltp":"Tune autovacuum_vacuum_max_threshold from table size, change rate, and maintenance SLA, using per-table thresholds for large/hot relations. Observe trigger intervals, dead tuples, and ANALYZE/VACUUM duration.","small":"Start with upstream. Fixed thresholds dominate on small tables; after changes, confirm worker and I/O headroom."},"mechanism":["Maximum number of tuple updates or deletes prior to vacuum. A configuration reload applies a new value; existing work already in flight is not retroactively changed.","The ordinary automatic-vacuum threshold is the base term plus scale factor times reltuples, capped by autovacuum_vacuum_max_threshold from PG18. It reacts to dead tuples from updates/deletes, permits per-table overrides, and is separate from mandatory anti-wraparound vacuuming.","Monitor and change autovacuum_vacuum_max_threshold together with autovacuum_vacuum_threshold, autovacuum_vacuum_scale_factor, autovacuum_vacuum_insert_threshold. Validate on the relevant server role and real workload, then use its sighup context to choose session change, reload, or restart; a historical boot default is not the current effective value."],"pitfalls":["Changing the global value while a table storage parameter overrides it.","Treating reltuples and cumulative change statistics as exact real-time counts.","Blaming a threshold without checking long transactions, replication slots, and worker saturation.","Buying short-term quiet by deferring maintenance until wraparound failsafe activates."],"references":[{"title":"PostgreSQL 19 Beta 4: autovacuum_vacuum_max_threshold","url":"https://www.postgresql.org/docs/19/runtime-config-vacuum.html#GUC-AUTOVACUUM-VACUUM-MAX-THRESHOLD"},{"title":"PostgreSQL 19 release notes","url":"https://www.postgresql.org/docs/19/release-19.html"}],"related":["autovacuum_vacuum_threshold","autovacuum_vacuum_scale_factor","autovacuum_vacuum_insert_threshold","autovacuum_vacuum_insert_scale_factor","autovacuum","autovacuum_analyze_scale_factor"],"summary":"autovacuum_vacuum_max_threshold — Maximum number of tuple updates or deletes prior to vacuum. Observed in PG18–19 Beta 4; its last measured boot default is 100000000 in PG19 Beta 4, with sighup context. This is a beta-snapshot fact and can change before PostgreSQL 19 GA."},"enumvals":[],"first_version":"18","group":"Vacuuming","group_slug":"vacuum","imported_at":"2026-09-27T17:57:30.83658+08:00","intro_commit":{"authored_at":"2025-02-05T15:48:18-06:00","discussion":["https://postgr.es/m/956435f8-3b2f-47a6-8756-8c54ded61802%40dalibo.com"],"hash":"306dc520b9dfd6014613961962a89940a431a069","subject":"Introduce autovacuum_vacuum_max_threshold.","url":"https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=306dc520b9dfd6014613961962a89940a431a069"},"key":"autovacuum_vacuum_max_threshold","last_version":"20","max_val":"","min_val":"","name":"autovacuum_vacuum_max_threshold","position":32,"present_in":["18","19","20"],"short_desc":"Specifies the maximum number of updated or deleted tuples needed to trigger a VACUUM in any one table, i.e., a limit on the value calculated with autovacuum_vacuum_threshold and autovacuum_vacuum_scale_factor.","short_desc_zh":"","source_rev":"english-manuals:759c54f1471bde9cc85361b4593c7ce909bf16adc3c3f250c6e695e89eed6874","unit":"","vartype":"integer"}},"Definition":{"Collection":"guc","Key":"autovacuum_vacuum_max_threshold","SourceDatabase":"center","Version":"18","SourceTable":"guc","SourceKey":"autovacuum_vacuum_max_threshold","SourceRevision":"english-manuals:759c54f1471bde9cc85361b4593c7ce909bf16adc3c3f250c6e695e89eed6874","Facts":{"boot_val":"100000000","category":"Vacuuming / Automatic Vacuuming","context":"sighup","description":"Specifies the maximum number of updated or deleted tuples needed to trigger a VACUUM in any one table, i.e., a limit on the value calculated with autovacuum_vacuum_threshold and autovacuum_vacuum_scale_factor. The default is 100,000,000 tuples. If -1 is specified, autovacuum will not enforce a maximum number of updated or deleted tuples that will trigger a VACUUM operation. This parameter can only be set in the postgresql.conf file or on the server command line; but the setting can be overridden for individual tables by changing storage parameters.","doc":{"anchor":"GUC-AUTOVACUUM-VACUUM-MAX-THRESHOLD","file":"runtime-config-vacuum.html","lang":"en","sha256":"7047f1fa9138b97f1812532f8a905fa7479451dfd64655e029a7d387b20b22e4","slug":"18"},"documented":true,"enumvals":null,"extra_desc":"-1 disables the maximum threshold.","lang":"en","max_val":"2147483647","metadata_version":"18","min_val":"-1","name":"autovacuum_vacuum_max_threshold","short_desc":"Maximum number of tuple updates or deletes prior to vacuum.","source":"pg-settings-source-snapshot","unit":null,"vartype":"integer"},"ManualEvidence":{"doc":{"anchor":"GUC-AUTOVACUUM-VACUUM-MAX-THRESHOLD","file":"runtime-config-vacuum.html","lang":"en","sha256":"7047f1fa9138b97f1812532f8a905fa7479451dfd64655e029a7d387b20b22e4","slug":"18"}},"MeasuredEvidence":{"metadata_version":"18"}},"Text":{"Collection":"guc","Key":"autovacuum_vacuum_max_threshold","SourceDatabase":"pgweb","Version":"18","Locale":"zh-Hans","Title":"autovacuum_vacuum_max_threshold","Summary":"","BodyHTML":"\u003cp\u003e指定在任意一个表上触发\u003ccode\u003eVACUUM\u003c/code\u003e所需更新或删除元组数的最大值，也就是对 \u003ccode\u003eautovacuum_vacuum_threshold\u003c/code\u003e和 \u003ccode\u003eautovacuum_vacuum_scale_factor\u003c/code\u003e计算结果所施加的上限。默认值为 100,000,000 个元组。如果指定为\u003ccode\u003e-1\u003c/code\u003e，自动清理将不会对触发 \u003ccode\u003eVACUUM\u003c/code\u003e所需的更新或删除元组数强制施加最大值。该参数只能在\u003ccode\u003epostgresql.conf\u003c/code\u003e文件中或服务器命令行上设置；但可以通过更改表存储参数覆盖单个表的该设置。\u003c/p\u003e","SourceRevision":"2026-09-11@29c86d9","ContentHash":"dbb0904e4154b88011d20516ed4cba9a19d466b6048fca73c8568df43ffb5260","Payload":{"carried_from":"","carry_reason":"","doc_html":"\u003cp\u003e指定在任意一个表上触发\u003ccode class=\"command\"\u003eVACUUM\u003c/code\u003e所需更新或删除元组数的最大值，也就是对 \u003ccode class=\"varname\"\u003eautovacuum_vacuum_threshold\u003c/code\u003e和 \u003ccode class=\"varname\"\u003eautovacuum_vacuum_scale_factor\u003c/code\u003e计算结果所施加的上限。默认值为 100,000,000 个元组。如果指定为\u003ccode class=\"literal\"\u003e-1\u003c/code\u003e，自动清理将不会对触发 \u003ccode class=\"command\"\u003eVACUUM\u003c/code\u003e所需的更新或删除元组数强制施加最大值。该参数只能在\u003ccode class=\"filename\"\u003epostgresql.conf\u003c/code\u003e文件中或服务器命令行上设置；但可以通过更改表存储参数覆盖单个表的该设置。\u003c/p\u003e","doc_same_as":""}},"RequestedLocale":"zh-Hans","Fallback":false,"Versions":["18","19","20"],"Locales":["en","zh-Hans"],"Signatures":null,"Spellings":null,"SQLState":null,"Evidence":null}