Re: Postgresql 14 performance

On Sun, Aug 21, 2022 at 9:16 PM Mladen Gogala <gogala(dot)mladen(at)gmail(dot)com>
wrote:

> On 8/21/22 20:46, Jeff Janes wrote:
>
>
> You can see there that little time was spent reading data, so that
> explains why repeating the query didn't make it much faster due to
> caching. The time isn't spent reading data, but doing CPU work on data
> already in memory.
>
> Agreed. The "perf top" output produced by Kenny definitely indicates that.
> That's precisely why I concentrated on JIT. Anything else would give us a
> slim chance of increasing the query speed.
>

I don't think that that follows at all. Proper index usage can vastly
improve CPU-bound performance, not just Disk-bound performance. And that it
used to be faster in the recent past suggests that it is certainly possible
for it to be faster.

I assume he is on a system/installation without a JIT provider, so even if
jit is enabled in the postgresql.conf, it won't be used.

Cheers,

Jeff