On Fri, Jun 26, 2020 at 01:53:05PM -0700, Peter Geoghegan wrote: > On Thu, Jun 25, 2020 at 1:36 PM Andres Freund <and...@anarazel.de> wrote: > > 12 28164.865 ms > > > > fast ssd: > > HEAD 92520.680 ms > > > > magnetic: > > HEAD 183968.538 ms > > > > (no reads, there's plenty enough memory. Just writes because the age / > > amount thresholds for dirty data are reached) > > > > In the magnetic case we're IO bottlenecked nearly the whole time. > > I agree with almost everything you've said on this thread, but at the > same time I question the emphasis on I/O here. You've shown that > spinning rust is about twice as slow as a fast SSD here. Fair enough, > but to me the real story is that spilling is clearly a lot slower in > general, regardless of how fast the storage subsystem happens to be (I > wonder how fast it is with a ramdisk). To me, it makes more sense to
This blog entry shows ORDER BY using ram disk, SSD, and magnetic: https://momjian.us/main/blogs/pgblog/2012.html#February_2_2012 It is from 2012, but I can re-run the test if you want. -- Bruce Momjian <br...@momjian.us> https://momjian.us EnterpriseDB https://enterprisedb.com The usefulness of a cup is in its emptiness, Bruce Lee