Hi, On 2020-07-24 18:37:02 -0400, Tom Lane wrote: > David Rowley <dgrowleyml@xxxxxxxxx> 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