Re: RDS IO Read time

> On Mar 31, 2025, at 06:54, Eden Aharoni <edena(at)legitsecurity(dot)com> wrote:
> Is this expected IO read rate? I can’t help but feel we’re missing something here..

Really, no particular I/O rate is "expected": if PostgreSQL needs that much data, it'll use that much I/O to get it. From your description, it's likely that it's a case of the working set for the database just not fitting into the memory you have, so PostgreSQL needs to go out to secondary storage a lot to fetch the data.

The best first step is to use Performance Insights to see which queries are using I/O, and run sample ones with EXPLAIN (ANALYZE, BUFFERS) to see where the I/O is being used within the query. Given that you allow users to assemble arbitrary queries, it's likely that PostgreSQL is having to use a wide variety of indexes (or sequential scans), so it can't successfully cache a particular set in memory.