Horton

Re: JIT compiling with LLVM v9.0

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Andres Freund <andres@anarazel.de>, Thomas Munro <thomas.munro@enterprisedb.com>, Jeff Davis <pgsql@j-davis.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2018-02-10T23:11:43Z
Lists: pgsql-hackers 
On Wed, Jan 31, 2018 at 8:53 AM, Robert Haas <robertmhaas@gmail.com> wrote:
> As far as the second one, looking back at what happened with parallel
> query, I found (on a quick read) 13 back-patched commits in
> REL9_6_STABLE prior to the release of 10.0, 3 of which I would qualify
> as low-importance (improving documentation, fixing something that's
> not really a bug, improving a test case).  A couple of those were
> really stupid mistakes on my part.  On the other hand, would it have
> been overall worse for our users if that feature had been turned on in
> 9.6?  I don't know.  They would have had those bugs (at least until we
> fixed them) but they would have had parallel query, too.  It's hard
> for me to judge whether that was a win or a loss, and so here.  Like
> parallel query, this is a feature which seems to have a low risk of
> data corruption, but a fairly high risk of wrong answers to queries
> and/or strange errors.   Users don't like that.  On the other hand,
> also like parallel query, if you've got the right kind of queries, it
> can make them go a lot faster.  Users DO like that.

As a data point, I can tell you that Heroku enabled parallel query for
9.6 immediately, and it turned out fine. The first version available
as stable was probably 9.6.3 -- there or thereabouts.

There were some bugs, of course, but not to the extent that 9.6 was
looked upon as being more buggy than the average Postgres release.

-- 
Peter Geoghegan

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".