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#postgresql takes a bite of 30,000 rows from your 50 million row table and calls it a day. That's 0.06% of your data deciding if your query will be fast or slow. boringsql.com/posts/postgr...

boringsql.comPostgreSQL Statistics: Why queries run slowSlow PostgreSQL queries? Stale statistics are often to blame. Learn how the query planner uses statistics to estimate row counts and how to fix them.

27/2/26, 7:03 pm0 reposts1 like

Radim @ boringSQL

@boringsql.com

27 Feb

Or what about cases where there are no statistics at all? Like materialized CTEs, temporary tables, or computed expressions in WHERE clauses. The planner falls back to hardcoded constants. 0.5% selectivity for equality. 33% for ranges. Good luck.

Andrew Atkinson

@andyatkinson.com

27 Feb

"0.5% selectivity for equality. 33% for ranges. Good luck." Could make a good snarky Postgres t-shirt to wear at Postgres conferences. 😂

Radim @ boringSQL

@boringsql.com

27 Feb

You just might be onto something 🤣 I've been looking for something for the back of the t-shirts and I think we have a strong candidate Equality: 0.5% Ranges: 33% May your indexes be with you