Horton

Re: JIT compiling with LLVM v12

Andres Freund <andres@anarazel.de>

View thread View on postgr.es
From: Andres Freund <andres@anarazel.de>
To: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Cc: Noah Misch <noah@leadboat.com>, pgsql-hackers@postgresql.org
Date: 2018-08-22T14:54:11Z
Lists: pgsql-hackers 
Hi,

On 2018-08-22 16:36:00 +0200, Peter Eisentraut wrote:
> I'm suspicious that we haven't had much feedback about this.  We've
> heard of one or two cases where LLVM broke a query outright, and that
> was fixed and that was a good result.  But we haven't heard anything
> about performance regressions.  Surely there must be some.  There hasn't
> been any discussion or further analysis of the default cost settings
> either.  I feel that we don't have enough information.

Yea. I don't think we'll get really good feedback before production
unfortunately :(


> I would like, however, that we make a decision one way or the other
> before the next beta.  I've been handwaving a bit to users not to rely
> on the current betas for performance testing because the defaults might
> change later.  That's bad either way.

I don't see particularly much benefit in deciding before beta,
personally.  What's making you think it'd be important to decide before?
Pretty fundamentally, it'll be a setting you don't know is effectively
on, for the forseeable future anyway?

Greetings,

Andres Freund

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".