Cookbook recipe

Reclaim bloat without downtime

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

What This Is

A production experience capsule based on real incident patterns.

Why It Matters

Builds production judgment under pressure.

Next Step

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Estimated investigation4 min

Scenario

A table grew to 3x its real data size from churn. VACUUM FULL would reclaim it but takes an exclusive lock. pg_repack does it online. Diagnose it Estimate bloat, then choose a tool: -- rough table…

Investigation Path

A table grew to 3x its real data size from churn. VACUUM FULL would reclaim it but takes an exclusive lock. pg_repack does it online.

Diagnose it

Estimate bloat, then choose a tool:

-- rough table size vs live tuples
SELECT relname, pg_size_pretty(pg_total_relation_size(relid)) AS total,
       n_live_tup, n_dead_tup
FROM pg_stat_user_tables ORDER BY pg_total_relation_size(relid) DESC LIMIT 10;

Why it happens

Plain VACUUM marks dead tuples reusable but does not return space to the OS. VACUUM FULL rewrites the table compactly but holds an ACCESS EXCLUSIVE lock. pg_repack rebuilds online with only brief locking.

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Related & next steps

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Concepts on this page

Autovacuum VACUUM Index Bloat Lock
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