Browse Teach Curate

Database Buffer Pool

The buffer pool caches recently used disk pages in memory, so a page access is either a cheap cache hit or a disk read thousands of times slower. Plan timings vary between cold and warm cache, which is why EXPLAIN ANALYZE buffer counts (hits vs reads) matter as much as milliseconds.

Questions this Concept answers

Why does a query that reads a huge table hurt the response time of unrelated queries?

jeremy Video

How the PostgreSQL Buffer Cache Pins Pages and Tracks the Dirty Bit

PostgreSQL's buffer cache (shared buffers) is a fixed-size array of 8 KB page frames in primary memory through which *all* secondary-storage blocks must pass; no query or update operation can touch a…