> On Aug 22, 2018, at 7:13 PM, Andres Freund <and...@anarazel.de> wrote: > > On 2018-08-22 18:29:58 -0400, Jonathan S. Katz wrote: >> >>> On Aug 22, 2018, at 2:58 PM, Andreas Joseph Krogh <andr...@visena.com> >>> wrote: >>> >>> På onsdag 22. august 2018 kl. 20:52:05, skrev Andres Freund >>> <and...@anarazel.de <mailto:and...@anarazel.de>>: >>> 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 >> https://explain.depesz.com/s/vgzD <https://explain.depesz.com/s/vgzD> >> >> 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 >> https://explain.depesz.com/s/AvZM <https://explain.depesz.com/s/AvZM> >> >> 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 > > 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. Jonathan
signature.asc
Description: Message signed with OpenPGP
