On Wed, Jul 3, 2019 at 11:24 AM Tomas Vondra <tomas.von...@2ndquadrant.com> wrote: > Maybe. And it would probably work for the systems I used for benchmarks. > > It however assumes two things: (a) the storage system actually has > spindles and (b) you know how many spindles there are. Which is becoming > less and less safe these days - flash storage becomes pretty common, and > even when there are spindles they are often hidden behind the veil of > virtualization in a SAN, or something.
Yeah, that's true. > I wonder if we might provide something like pg_test_prefetch which would > measure performance with different values, similarly to pg_test_fsync. That's not a bad idea, but I'm not sure if the results that we got in a synthetic test - presumably unloaded - would be a good guide to what to use in a production situation. Maybe it would; I'm just not sure. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
