Tomas Vondra
PostgreSQL Hacker @ Microsoft
Long-term PostgreSQL contributor & committer, focusing on performance, query planning & optimization, etc.
POSETTE 2026 Talk
random_page_cost in Postgres - why the default is 4.0 and should you lower it?
random_page_cost is one of the basic parameters affecting query planning in PostgreSQL. It expresses the cost of random I/O in relation to sequential reads. The lower the value, the "cheaper" the operations performing random I/O – typically Index Scans. Since 2002 the default value is set to 4.0, but how did we pick it and why didn't it change over the ~25 years? The storage changed a lot over the years. And should you reduce it when running on SSDs?
Past Talks
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Performance Archaeology - 20 years of improvements (POSETTE 2025)
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Where do the performance cliffs come from? (POSETTE 2024)
Podcast Appearances
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Why it's fun to hack on Postgres performance with Tomas Vondra
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