Re: [HACKERS] Binary search in fmgr_isbuiltin() is a bottleneck. - Mailing list pgsql-hackers

From Andres Freund
Subject Re: [HACKERS] Binary search in fmgr_isbuiltin() is a bottleneck.
Date
Msg-id 20170928225636.5zpkcgorw5odfb5s@alap3.anarazel.de
Whole thread Raw
In response to Re: [HACKERS] Binary search in fmgr_isbuiltin() is a bottleneck.  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: [HACKERS] Binary search in fmgr_isbuiltin() is a bottleneck.
List pgsql-hackers
On 2017-09-28 18:52:28 -0400, Tom Lane wrote:
> Andres Freund <andres@anarazel.de> writes:
> > I might be worse than you... But anyway, here's a patch doing
> > so. Looking at profiles, it turned out that having the integer limits as
> > extern variables in a different TU isn't a great idea.
> 
> Uh, what?  Access to fmgr_nbuiltins shouldn't be part of any critical path
> anymore after this change.

Indeed. But the size of the the oid -> fmgr_builtins index array is
relevant now. We could of course just make that dependent on
FirstBootstrapObjectId, but that'd waste some memory.


> > So I moved what
> > used to be fmgrtab.c to fmgrtab.h, and included it directly in fmgr.c.
> 
> I'm kind of -0.5 on that.  I believe part of the argument for having
> things set up as they were was to allow external code to access the
> fmgr_builtins table (as my speed-test hack earlier today did).

You could still do that, you'd just end up with a second copy. Doesn't
seem bad for such an uncommon case.


Greetings,

Andres Freund


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