Horton

Re: WIP: Faster Expression Processing and Tuple Deforming (including JIT)

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Nico Williams <nico@cryptonector.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, pgsql-hackers@postgresql.org, Heikki Linnakangas <hlinnaka@iki.fi>, Doug Doole <ddoole@salesforce.com>
Date: 2016-12-06T20:40:06Z
Lists: pgsql-hackers 
On 2016-12-06 14:35:43 -0600, Nico Williams wrote:
> On Tue, Dec 06, 2016 at 12:27:51PM -0800, Andres Freund wrote:
> > On 2016-12-06 14:19:21 -0600, Nico Williams wrote:
> > > > I concur with your feeling that hand-rolled JIT is right out.  But
> > > 
> > > Yeah, that way lies maintenance madness.
> > 
> > I'm not quite that sure about that. I had a lot of fun doing some
> > hand-rolled x86 JITing. Not that is a ward against me being mad.  But
> > more seriously: Manually doing a JIT gives you a lot faster compilation
> > times, which makes JIT applicable in a lot more situations.
> 
> What I meant is that each time there are new ISA extensions, or
> differences in how relevant/significant different implementations of the
> same ISA implement certain instructions, and/or every time you want to
> add a new architecture... someone has to do a lot of very low-level
> work.

Yea, that's why I didn't pursue this path further. I *personally* think
it'd be perfectly fine to only support JITing on linux x86_64 and
aarch64 for now. And those I'd be willing to work on. But since I know
that's not project policy...

- Andres

Commits

  1. Improve performance of ExecEvalWholeRowVar.

  2. Remove unreachable code in expression evaluation.

  3. Faster expression evaluation and targetlist projection.

  4. Avoid syntax error on platforms that have neither LOCALE_T nor ICU.

  5. Add configure test to see if the C compiler has gcc-style computed gotos.

  6. Improve regression test coverage for TID scanning.

  7. Improve expression evaluation test coverage.

  8. Fix two errors with nested CASE/WHEN constructs.