Re: PG 15 (and to a smaller degree 14) regression due to ExprEvalStep size

On Fri, Jul 22, 2022 at 1:13 PM David Rowley <dgrowleyml(at)gmail(dot)com> wrote:
> On Fri, 22 Jul 2022 at 15:22, Amit Langote <amitlangote09(at)gmail(dot)com> wrote:
> > BTW, the only way I found to *forcefully* exercise llvm_compile_expr()
> > is to add `set jit_above_cost to 0` at the top of the test file, or
> > are we missing a force_jit_mode, like there is force_parallel_mode?
>
> I don't think we'd need any setting to hide the JIT counters from
> EXPLAIN ANALYZE since those only show with COSTS ON, which we tend not
> to do.

Ah, makes sense.

> I think for testing, you could just zero all the jit*above_cost GUCs.
>
> If you look at the config_extra in [1], you'll see that animal runs
> the tests with modified JIT parameters.
>
> BTW, I was working on code inside llvm_compile_expr() a few days ago
> and I thought I'd gotten the new evaluation steps I was adding correct
> as it worked fine with jit_above_cost=0, but on further testing, it
> crashed with jit_inline_above_cost=0. Might be worth doing both to see
> if everything works as intended.

Thanks for the pointer.

So I didn't see things going bust on re-testing with all
jit_*_above_cost parameters set to 0, so maybe the
llvm_compile_expression() additions are alright.

--
Thanks, Amit Langote
EDB: http://www.enterprisedb.com