Hi, On 2020-06-05 15:30:44 -0700, Andres Freund wrote: > On 2020-06-05 15:21:34 -0600, Jens Axboe wrote: > > >> I can reproduce this, and I see what it is. I'll send out a patch soonish. > > > > > > Thinko, can you try with this on top? > > > > Sorry that was incomplete, please use this one! > > That seems to fix it! Yay. > > > Bulk buffered reads somehow don't quite seem to be performing that well > though, looking into it. Could be on the pg side too. While looking into that, I played with setting /sys/<dev>/queue/read_ahead_kb to 0 and noticed that seems to result in all/most IO done in workers. Is that to be expected? Greetings, Andres Freund