[ethanseal]

When you say cold cache, did you clear the os page cache as well as the postgres buffercaches? After setup.sql, the cache will be warmish - I get 4ms on the first run. I'm using postgres 17.5

See https://github.com/ethan-seal/ors_expensive/blob/main/benchm... where I use dd to clear the os page cache.

This article by pganalyze talks about it: https://pganalyze.com/blog/5mins-postgres-17-pg-buffercache-...

[hans_castorp]

I did not explicitly evict the Postgres buffer cache, but using pg_buffercache to evict all buffers for the table, yields a runtime of 23ms for me (still going for the BitmapOr).

https://notebin.de/?ac3fcf55e6850f47#ERXndRrqp3X4zEWX5EC3dZU...

Which plan does Postgres choose in your case that results 100ms?

[ethanseal]

Exactly the same one from what I see: https://github.com/ethan-seal/ors_expensive/blob/main/explai...

Given the buffer reads seem close to yours, I believe it's page cache.