Hi,
On 2020-07-24 18:37:02 -0400, Tom Lane wrote:
> David Rowley <dgrowleyml@gmail.com> writes:
> > However, for now, you might just want to try raising various jit
> > thresholds so that it only is enabled for more expensive plans.
>
> Yeah. I'm fairly convinced that the v12 defaults are far too low,
> because we are constantly seeing complaints of this sort.
I think the issue is more that we need to take into accoutn that the
overhead of JITing scales ~linearly with the number of JITed
expressions. And that's not done right now. I've had a patch somewhere
that had a prototype implementation of changing the costing to be
#expressions * some_cost, and I think that's a lot more accurate.
Greetings,
Andres Freund