DeepSQL's benchmark finds BRIN's 5% update cliff in Postgres

Venkat Sakamuri's 10M-row test found a 48 kB BRIN index touching 28 times more heap pages as cumulative updates rose from 1% to 5%.

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Primary source: DeepSQL

Why it matters

Teams using BRIN on range-queried, frequently updated tables need plan-level monitoring because index size and global correlation can conceal a sharp loss of pruning.

An exploded technical diagram showing a BRIN index block connecting to multiple database heap pages, with callouts for 1% and 5% update rates.

DeepSQL's Venkat Sakamuri has published a benchmark showing how quickly a compact PostgreSQL BRIN index can lose its block-skipping advantage when updates disturb the physical order of a table. In an article dated August 27th, Sakamuri found that cumulative updates to 5% of rows drove a 28-fold jump in lossy heap pages, even as PostgreSQL reported a correlation of 0.921.…

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