Horton

Re: Inlining comparators as a performance optimisation

Bruce Momjian <bruce@momjian.us>

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From: Bruce Momjian <bruce@momjian.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Peter Geoghegan <peter@2ndquadrant.com>, PG Hackers <pgsql-hackers@postgresql.org>
Date: 2011-12-02T20:42:21Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Speed up conversion of signed integers to C strings.

  2. Remove some unnecessary tests of pgstat_track_counts.

  3. Remove cvs keywords from all files.

  4. Code cleanup for function prototypes: change two K&R-style prototypes

  5. Use Min() instead of min() in qsort, for consistency and to avoid

  6. pgindent run for 8.2.

  7. Switch over to using our own qsort() all the time, as has been proposed

Robert Haas wrote:
> On Fri, Dec 2, 2011 at 2:35 PM, Bruce Momjian <bruce@momjian.us> wrote:
> > Agreed. ?Doing something once and doing something in the sort loop are
> > two different overheads.
> 
> OK, so I tried to code this up.  Adding the new amproc wasn't too
> difficult (see attached).  It wasn't obvious to me how to tie it into
> the tuplesort infrastructure, though, so instead of wasting time
> guessing what a sensible approach might be I'm going to use one of my
> lifelines and poll the audience (or is that ask an expert?).
> Currently the Tuplesortstate[1] has a pointer to an array of
> ScanKeyData objects, one per column being sorted.  But now instead of
> "FmgrInfo sk_func", the tuplesort code is going to want each scankey
> to contain "SortSupportInfo(Data?) sk_sortsupport"[2], because that's
> where we get the comparison function from.   Should I just go ahead
> and add one more member to that struct, or is there some more
> appropriate way to handle this?

Is this code immediately usable anywhere else in our codebasde, and if
so, is it generic enough?

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + It's impossible for everything to be true. +