Hi, On 2020-09-23 11:19:18 -0700, Peter Geoghegan wrote: > On Fri, Sep 18, 2020 at 8:39 AM Andrey M. Borodin <x4...@yandex-team.ru> > wrote: > > Here is PoC with porting that same routine to B-tree. It allows to build > > B-trees ~10% faster on my machine.
I wonder what the effect of logging WAL records as huge as this (~256kb) is on concurrent sessions. I think it's possible that logging 32 pages at once would cause latency increases for concurrent OLTP-ish writes. And that a smaller batch size would reduce that, while still providing most of the speedup. > It doesn't seem to make any difference on my machine, which has an > NVME SSD (a Samsung 970 Pro). This is quite a fast SSD, though the > sync time isn't exceptional. Yea, they are surprisingly slow at syncing, somewhat disappointing for the upper end of the consumer oriented devices. > BTW, I noticed that the index build is absurdly bottlenecked on > compressing WAL with wal_compression=on. It's almost 3x slower with > compression turned on! Really should replace WAL compression with lz4 (or possibly zstd). Greetings, Andres Freund
