Horton

Re: WIP: Faster Expression Processing v4

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: Ants Aasma <ants.aasma@eesti.ee>, Heikki Linnakangas <hlinnaka@iki.fi>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2017-03-27T17:30:11Z
Lists: pgsql-hackers 
Andres Freund <andres@anarazel.de> writes:
> On 2017-03-27 12:18:37 -0400, Tom Lane wrote:
>> My feeling at this point is that we might be better off disabling
>> the computed-goto case by default.  At the very least, we're going
>> to need a version check that restricts it to latest gcc.

> In my measurements it's still faster in at least gcc-5/6, even without
> the option (largely because it avoids array bounds checks on the jump
> table built for the switch).

Hm.  What test cases are you using?

			regards, tom lane

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.