On 2019-02-06 17:37:04 +0900, Kyotaro HORIGUCHI wrote: > At Wed, 06 Feb 2019 15:16:53 +0900 (Tokyo Standard Time), Kyotaro HORIGUCHI > <horiguchi.kyot...@lab.ntt.co.jp> wrote in > <20190206.151653.117382256.horiguchi.kyot...@lab.ntt.co.jp> > > > The two should have the same extent of impact on performance when > > > disabled. I'll take numbers briefly using pgbench. > > (pgbench -j 10 -c 10 -T 120) x 5 times for each. > > A: unpached : 118.58 tps (stddev 0.44) > B: pached-not-used[1] : 118.41 tps (stddev 0.29) > C: patched-timedprune[2]: 118.41 tps (stddev 0.51) > D: patched-capped...... : none[3] > > [1]: cache_prune_min_age = 0, cache_entry_limit = 0 > > [2]: cache_prune_min_age = 100, cache_entry_limit = 0 > (Prunes every 100ms) > > [3] I didin't find a sane benchmark for the capping case using > vanilla pgbench. > > It doesn't seem to me showing significant degradation on *my* > box... > > # I found a bug that can remove newly created entry. So v11.
This seems to just benchmark your disk speed, no? ISTM you need to measure readonly performance, not read/write. And with plenty more tables than just standard pgbench -S. Greetings, Andres Freund
