Horton

Re: JIT compiling with LLVM v9.1

Jeff Davis <pgsql@j-davis.com>

View thread View on postgr.es
From: Jeff Davis <pgsql@j-davis.com>
To: Andres Freund <andres@anarazel.de>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2018-02-03T02:21:12Z
Lists: pgsql-hackers 
On Mon, Jan 29, 2018 at 1:53 AM, Andres Freund <andres@anarazel.de> wrote:
>>   https://git.postgresql.org/git/users/andresfreund/postgres.git

There's a patch in there to change the scan order. I suggest that you
rename the GUC "synchronize_seqscans" to something more generic like
"optimize_scan_order", and use it to control your feature as well
(after all, it's the same trade-off: weird scan order vs.
performance). Then, go ahead and commit it. FWIW I see about a 7%
boost on my laptop[1] from that patch on master, without JIT or
anything else.

I also see you dropped "7ae518bf Centralize slot deforming logic a
bit.". Was that intentional? Do we want it? I think I saw about a 2%
gain here over master, but when I applied it on top of the fast scans
it did not seem to add anything on top of fast scans. Seems
reproducible, but I don't have an explanation.

And you are probably already working on this, but it would be helpful
to get the following two patches in also:
* 3c22065f Do execGrouping via expression eval
* a9dde4aa Allow tupleslots to have a fixed tupledesc

I took a brief look at those two, but will review them in more detail.

Regards,
     Jeff Davis

[1] Simple scan with simple predicate on 50M tuples, after pg_prewarm.

Commits

  1. Improve JIT docs.

  2. Add documentation for the JIT feature.

  3. Add EXPLAIN support for JIT.

  4. Add inlining support to LLVM JIT provider.

  5. JIT tuple deforming in LLVM JIT provider.

  6. Add FIELDNO_* macro designating offset into structs required for JIT.

  7. Add expression compilation support to LLVM JIT provider.

  8. Expand list of synchronized types and functions in LLVM JIT provider.

  9. Add helpers for emitting LLVM IR.

  10. Basic planner and executor integration for JIT.

  11. Debugging and profiling support for LLVM JIT provider.

  12. Support for optimizing and emitting code in LLVM JIT provider.

  13. Add file containing extensions of the LLVM C API.

  14. Basic JIT provider and error handling infrastructure.

  15. Add configure infrastructure (--with-llvm) to enable LLVM support.

  16. Add C++ support to configure.

  17. Add PGAC_PROG_VARCC_VARFLAGS_OPT autoconf macro.

  18. Fix VM buffer pin management in heap_lock_updated_tuple_rec().

  19. Allow tupleslots to have a fixed tupledesc, use in executor nodes.

  20. Expression evaluation based aggregate transition invocation.

  21. Perform slot validity checks in a separate pass over expression.

  22. Rely on executor utils to build targetlist for DML RETURNING.

  23. Refer to OS X as "macOS", except for the port name which is still "darwin".