Cookbook recipe

Tame autovacuum on a high-churn table

Applies to PostgreSQL 13–17 Last reviewed May 2026 Grounded in source

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Estimated investigation4 min

Scenario

One hot table churns constantly and bloats faster than the global autovacuum settings can keep up. Per-table tuning fixes it without touching the whole cluster. Diagnose it Check dead tuples and last autovacuum: SELECT relname, n_dead_tup,…

Investigation Path

One hot table churns constantly and bloats faster than the global autovacuum settings can keep up. Per-table tuning fixes it without touching the whole cluster.

Diagnose it

Check dead tuples and last autovacuum:

SELECT relname, n_dead_tup, n_live_tup, last_autovacuum
FROM pg_stat_user_tables
ORDER BY n_dead_tup DESC LIMIT 10;

Why it happens

Autovacuum triggers at autovacuum_vacuum_threshold + scale_factor * n_live_tup. On a big, hot table the scale factor makes the threshold huge, so vacuum runs too rarely and bloat accumulates.

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Related & next steps

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Concepts on this page

Autovacuum VACUUM Bloat
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