Horton

Re: JIT compiling expressions/deform + inlining prototype v2.0

Andres Freund <andres@anarazel.de>

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From: andres@anarazel.de (Andres Freund)
To: Konstantin Knizhnik <k.knizhnik@postgrespro.ru>
Cc: pgsql-hackers@postgresql.org
Date: 2017-09-05T16:41:37Z
Lists: pgsql-hackers 
On 2017-09-05 13:58:56 +0300, Konstantin Knizhnik wrote:
> 
> 
> On 04.09.2017 23:52, Andres Freund wrote:
> > 
> > Yea, I've changed that already, although it's currently added earlier,
> > because the alignment is needed before, to access the column correctly.
> > I've also made number of efficiency improvements, primarily to access
> > columns with an absolute offset if all preceding ones are fixed width
> > not null columns - that is quite noticeable performancewise.
> 
> Unfortunately, in most of real table columns are nullable.

I'm not sure I agree with that assertion, but:


> I wonder if we can perform some optimization in this case (assuming that in
> typical cases column either contains mostly non-null values, either mostly
> null values).

Even if all columns are NULLABLE, the JITed code is still a good chunk
faster (a significant part of that is the slot->tts_{nulls,values}
accesses). Alignment is still cheaper with constants, and often enough
the alignment can be avoided (consider e.g. a table full of nullable
ints - everything is guaranteed to be aligned, or columns after an
individual NOT NULL column is also guaranteed to be aligned). What
largely changes is that the 'offset' from the start of the tuple has to
be tracked.

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".