Heap storage & bloatsenior🔒 Pro concept

HOT updates & page pruning

Simple terms

Update a row without touching any indexed column, and if its page still has room, Postgres writes the new version right there, and creates no index entry at all. None. That is a HOT update, and it is why some updates are dramatically cheaper than others: the index churn simply doesn't happen. The dead version left behind doesn't need VACUUM either. The next query that walks that page clears it up on the way past.

You might be asked

What is a HOT (heap-only tuple) update, when does Postgres choose it, and how does opportunistic page pruning reclaim dead row versions without VACUUM?

TopicHeap storage / MVCC bloat control
PostgreSQL14, 15, 16, 17, 18
Tools usedpageinspect (heap_page_items, get_raw_page, page_header), pg_stat_user_tables, source navigation @REL_17_10
Last reviewed2026-06-19

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  • Version notes, what changed across PostgreSQL releases
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