Re: effect of JIT tuple deform?

Hi

I played with it and maybe I got interesting result.

When I played with really big table, then I got IO waits and effect of jit_tuple_deforming is near to zero (as expected)

When I played with smaller table under RAM, then I can see positive effect of JIT_TD, but only when optimization is active. When optimization was false, then JIT_TD has negative slowdown.

Shared buffers 1GB

table wt .. 100columns, 2M rows, cca 823MB

set max_parallel_workers to 0;

query:

select sum(c99) from wt;

default (jit active) ... 1853ms

set jit_tuple_deforming to off .. 1397ms

set jit off .. 1400ms

== enforced inline ==

jit_tuple_deforming on .. 1610ms

jit_tuple_deforming off .. 1420ms

== enforced optimize ==

jit_tuple_deforming on .. 842ms

jit_tuple_deforming off .. 1420ms

I played with setting and I got the best speed with

jit_inline_above_cost ..some pretty high number

jit_optimize_above_cost 0

jit_tuple_deforming on

So I am able to see effect of jit_tuple_deforming, and very well, but only if optimization is active. When optimization is not active then jit_tuple_deforming does slowdown.

So maybe a usage of jit_tuple_deforming can be conditioned by jit_optimization?

Regards

Pavel