On Sat, Jul 30, 2022 at 08:54:33PM +0800, Julien Rouhaud wrote: > > It turns out that having pg_stat_statements with INSTRUMENT_EXTRA indirectly > requested by INSTRUMENT_ALL adds a ~27% overhead. > > I'm not sure that I actually believe these results, but they're really > consistent, so maybe that's real. > > Anyway, even if the overheadwas only 1.5% like in your own benchmark, that > still wouldn't be acceptable. Such a feature is in my opinion very welcome, > but it shouldn't add *any* overhead outside of EXPLAIN (ANALYZE, VERBOSE).
I did the same benchmark this morning, although trying to stop all background jobs and things on my machine that could interfere with the results, using longer runs and more runs and I now get a reproducible ~1% overhead, which is way more believable. Not sure what happened yesterday as I got reproducible number doing the same benchmark twice, I guess that the fun doing performance tests on a development machine. Anyway, 1% is in my opinion still too much overhead for extensions that won't get any extra information.
