I guess this cannot be pointed out too often ;) I'm not intending to do this but the behaviour of the system with fsync=off led me to further understand that the bottleneck had to be CPU-related rather than I/O-related. Of course, I never switched off fsync on the production system. Best wishes, ________________________________________ From: Laurenz Albe [laurenz.albe@xxxxxxxxxxx] Sent: Wednesday, August 28, 2019 05:45 To: Holtgrewe, Manuel; Luca Ferrari Cc: pgsql-general Subject: Re: [ext] Re: Pointers towards identifying bulk import bottleneck (walwriter tuning?) Holtgrewe, Manuel wrote: > Switching off fsync leads to a drastic time improvement but still > higher wall-clock time for four threads. Don't do that unless you are ready to start from scratch with a new "initdb" in the case of a crash. You can do almost as good by setting "synchronous_commit = off", and that is crash-safe. Yours, Laurenz Albe -- Cybertec | https://www.cybertec-postgresql.com
