Hi, On 2020-04-06 06:39:59 -0700, Andres Freund wrote: > > 3) Plain pgbench read-write (you already did it for sure) > > -s 100 -M prepared -T 700 > > autovacuum=off, fsync on: > clients tps master tps pgxact > 1 474 479 > 16 4356 4476 > 40 8591 9309 > 198 20045 20261 > 1024 17986 18545 > > autovacuum=off, fsync off: > clients tps master tps pgxact > 1 7828 7719 > 16 49069 50482 > 40 68241 73081 > 198 73464 77801 > 1024 25621 28410 > > I chose autovacuum off because otherwise the results vary much more > widely, and autovacuum isn't really needed for the workload.
> These numbers seem pretty decent to me. The regressions seem mostly > within noise. The one possible exception to that is plain pgbench > read/write with fsync=off and only a single session. I'll run more > benchmarks around that tomorrow (but now it's 6am :(). The "one possible exception" turned out to be a "real" regression, but one that was dead easy to fix: It was an DEBUG1 elog I had left in. The overhead seems to solely have been the increased code size + overhead of errstart(). After that there's no difference in the single client case anymore (I'd not expect a benefit). Greetings, Andres Freund