Cookbook recipe

Index bloat vs table bloat: telling them apart

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

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A production experience capsule based on real incident patterns.

Why It Matters

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Estimated investigation4 min

Scenario

Storage is up but is it the table or its indexes? They bloat differently and need different fixes. Diagnose it Compare heap vs index sizes over time: SELECT pg_size_pretty(pg_relation_size('t')) AS heap, pg_size_pretty(pg_indexes_size('t')) AS idx; Why it…

Investigation Path

Storage is up but is it the table or its indexes? They bloat differently and need different fixes.

Diagnose it

Compare heap vs index sizes over time:

SELECT pg_size_pretty(pg_relation_size('t')) AS heap,
       pg_size_pretty(pg_indexes_size('t')) AS idx;

Why it happens

Table bloat comes from dead tuples VACUUM has not reclaimed (or cannot return to the OS). Index bloat comes from page splits and dead entries; b-trees do not shrink on their own and degrade with churn.

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Related & next steps

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Concepts on this page

Autovacuum VACUUM Index Bloat Heap
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