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A low global factor can create unwanted maintenance during bulk jobs.","oltp":"Use lower per-table values on large, update-heavy tables so dead tuples do not accumulate into a large absolute backlog. Validate with table churn and vacuum duration rather than selecting a percentage in isolation.","small":"The upstream default is often adequate for genuinely small tables. Tune exceptions per table; a low cluster-wide value can create frequent tiny vacuums."},"mechanism":["The core trigger is the base threshold plus this factor multiplied by pg_class.reltuples, an approximate row count. In PostgreSQL 18 the result is also capped by autovacuum_vacuum_max_threshold.","This trigger counts tuples made obsolete by UPDATE or DELETE; insert-driven vacuuming has its own threshold and scale factor. Anti-wraparound vacuuming is governed by transaction-age rules and can run independently of this setting.","A table-level autovacuum_vacuum_scale_factor storage parameter overrides the global value, which is often preferable when table sizes and update rates vary widely."],"pitfalls":["A percentage that looks small can still represent millions of dead tuples on a large table.","Lowering the factor globally can create continuous I/O pressure across many tables.","It does not control insert-triggered vacuuming or anti-wraparound vacuuming.","reltuples is an estimate, so the trigger is not an exact dead-row percentage.","Table storage parameters can silently make the global value irrelevant for that table."],"references":[{"title":"PostgreSQL 19 Beta 4: autovacuum_vacuum_scale_factor","url":"https://www.postgresql.org/docs/19/runtime-config-vacuum.html#GUC-AUTOVACUUM-VACUUM-SCALE-FACTOR"},{"title":"PostgreSQL 18: Autovacuum trigger formulas","url":"https://www.postgresql.org/docs/18/routine-vacuuming.html#AUTOVACUUM"},{"title":"PostgreSQL 19 release notes","url":"https://www.postgresql.org/docs/19/release-19.html"}],"related":["autovacuum_vacuum_threshold","autovacuum_vacuum_max_threshold","autovacuum_vacuum_insert_scale_factor","autovacuum_analyze_scale_factor","autovacuum_naptime","autovacuum_freeze_max_age"],"summary":"Controls the table-size-proportional part of the normal autovacuum VACUUM trigger. 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