Re: Query is over 2x slower with jit=on

På torsdag 23. august 2018 kl. 03:00:42, skrev Jonathan S. Katz <
jkatz(at)postgresql(dot)org <mailto:jkatz(at)postgresql(dot)org>>:

> On Aug 22, 2018, at 7:13 PM, Andres Freund <andres(at)anarazel(dot)de> wrote:
[snip]
> For the archives sake: This likely largely is the consequence of
> building with LLVM's expensive assertions enabled, as confirmed by
> Jonathan over IM.

I recompiled with the release version of LLVM. jit=on was still slower,
but the discrepancy was not as bad as the previously reported result:

jit = off
Planning Time: 0.938 ms
Execution Time: 935.599 ms

jit = on
Planning Time: 0.951 ms
JIT:
  Functions: 184
  Generation Time: 17.605 ms
  Inlining: true
  Inlining Time: 20.522 ms
  Optimization: true
  Optimization Time: 1001.034 ms
  Emission Time: 665.319 ms
Execution Time: 2491.560 ms

However, it was still 2x+ slower, so still +1ing for open items.
 
 
I compiled with whatever switches LLVM that comes with Ubuntu 18.04 is built
with, and without debugging or assertions.
 
--
Andreas Joseph Krogh