Horton

Re: WIP: Faster Expression Processing v4

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: Tomas Vondra <tomas.vondra@2ndquadrant.com>, pgsql-hackers@postgresql.org
Date: 2017-03-14T17:34:10Z
Lists: pgsql-hackers 
On 2017-03-14 08:28:02 -0300, Alvaro Herrera wrote:
> Andres Freund wrote:
> 
> >     EEO_SWITCH(op->opcode)
> >     {
> > EEO_CASE(EEO_DONE):
> >         goto out;
> 
> Oh my.
> 
> > which is a bit annoying.  (the EEO_CASE is either a jump label or a case
> > statement, depending on computed goto availability).
> > 
> > It seems we could either:
> > 1) live with the damage
> > 2) disable pgindent
> > 3) move the : inside EEO_CASE's definition, and only use {} blocks.
> 
> I think 3) is nasty because the result doesn't look like normal C.

We have a bunch of such constructs already however. foreach(),
PG_TRY().  That means 3) has the advantage that our editors and pgindent
can already deal with it.


> EEO_CASE() are potentially jump labels, then indentation becomes
> correct.  Why not accept it?  It looks odd, but that gives a better hint
> to the reader about what's going on.

Seems likely that every editor would indent them differently :(


I'm leaning towards 3) for the reasons above and after trying out the
different indentations, but I don't have a strong opinion.


Greetings,

Andres Freund

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.