Re: JIT performance bug/regression & JIT EXPLAIN

Hi,

On 2019-09-27 00:20:53 -0700, Andres Freund wrote:
> Unfortunately I found a performance regression for JITed query
> compilation introduced in 12, compared to 11. Fixed in one of the
> attached patches (v1-0009-Fix-determination-when-tuple-deforming-can-be-JIT.patch
> - which needs a better commit message).
> 
> The first question is when to push that fix. I'm inclined to just do so
> now - as we still do JITed tuple deforming in most cases, as well as
> doing so in 11 in the places this patch fixes, the risk of that seems
> low. But I can also see an arguments for waiting after 12.0.

Since nobody opined, I now have pushed that, and the other fix mentioned
later in that email.

I'd appreciate comments on the rest of the email, it's clear that we
need to improve the test infrastructure here. And also the explain
output for grouping sets...

Greetings,

Andres Freund