Index-Only Scans

Postgres FM

Nikolay and Michael discuss Index-Only Scans in Postgres — what they are, how they help, some things to look out for, and some advice.
Here are some links to things they mentioned:

• Index-Only Scans and Covering Indexes (docs) https://www.postgresql.org/docs/current/indexes-index-only-scans.html
• Discussion on Twitter about JIT and Parallel Query defaults https://x.com/jer_s/status/1819749688184373742
• Postgres Wiki on Index-Only Scans https://wiki.postgresql.org/wiki/Index-only_scans
• Heap Fetches https://www.pgmustard.com/docs/explain/heap-fetches
• Rows Removed By Filter https://www.pgmustard.com/docs/explain/rows-removed-by-filter
• random_page_cost https://postgresqlco.nf/doc/en/param/random_page_cost/
• pg_dump docs change https://x.com/samokhvalov/status/1820539826363588755
• Crunchy Bridge changed random_page_cost to 1.1 for new servers https://docs.crunchybridge.com/changelog#postgres_random_page_cost_1_1
• Autovacuum Tuning Basics (updated blog post by Tomas Vondra) https://www.enterprisedb.com/blog/autovacuum-tuning-basics
• Our episode on over-indexing https://postgres.fm/episodes/over-indexing
• Our episode on HOT updates https://postgres.fm/episodes/hot-updates
• Our episode on partitioning https://postgres.fm/episodes/partitioning

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What did you like or not like? What should we discuss next time? Let us know via a YouTube comment, on social media, or by commenting on our Google doc!

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Postgres FM is produced by:

• Michael Christofides, founder of pgMustard
• Nikolay Samokhvalov, founder of Postgres.ai

With special thanks to:

• Jessie Draws for the elephant artwork