On 2018-08-22 19:51:12 +0200, Andreas Joseph Krogh wrote:
> I thought JITing of prepared queries happended once (in "prepare")
No, it happens when the first JITed function is executed.
> so it didn't have to do the JITing every time the query is
> executed. Isn't the previously generated bytecode usable for
> subsequent queries?
No, not currently. There's some reasons preventing that (primarily that
we currently rely on addresses of certain things not to change during
execution). There's ongoing work to change that, but that's certainly
not going to be ready for v11.
Greetings,
Andres Freund
Ok, thanks for clarifying.
Per earlier note[1] I was able to reproduce this issue with similar results to
Andreas while running 11 Beta 3.
jit = on
Planning Time: 0.921 ms
JIT:
Functions: 193
Generation Time: 121.595 ms
Inlining: false
Inlining Time: 0.000 ms
Optimization: false
Optimization Time: 58.045 ms
Emission Time: 1201.100 ms
Execution Time: 1628.017 ms
jit = off
Planning Time: 1.398 ms
Execution Time: 256.473 ms
I increased the the search range I used in the query by 3x, and got these numbers:
jit=on
Planning Time: 0.931 ms
JIT:
Functions: 184
Generation Time: 126.587 ms
Inlining: true
Inlining Time: 98.865 ms
Optimization: true
Optimization Time: 20518.982 ms
Emission Time: 7270.963 ms
Execution Time: 28772.576 ms
jit=off
Planning Time: 1.527 ms
Execution Time: 959.160 ms
So, I would +1 this for open items.
Jonathan
