Horton

Re: Cutting initdb's runtime (Perl question embedded)

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Andreas Karlsson <andreas@proxel.se>, pgsql-hackers@postgreSQL.org
Date: 2017-04-17T17:14:12Z
Lists: pgsql-hackers 
On 2017-04-17 17:49:54 +0100, Dagfinn Ilmari Mannsåker wrote:
> Tom Lane <tgl@sss.pgh.pa.us> writes:
> 
> > There's certainly lots more that could be done in the genbki code,
> > but I think all we can justify at this stage of the development
> > cycle is to get the low-hanging fruit for testing speedups.
> 
> I threw Devel::NYTProf at it and picked some more low-hanging fruit.
> Attached are separate patches for each change, and here are the runtimes
> of genbki.pl and Gen_fmgrtab.pl, respectively, after each patch
> (averages of 5 runs, in millseconds):

Btw, I think Tom's "more that could be done" was referring more to doing
more upfront work, checking, easier input format, whatnot in the genbki,
not so much performance work...  Tom, correct me if I'm wrong.

- Andres

Commits

  1. Attempt to identify system timezone by reading /etc/localtime symlink.

  2. Make sure to run one initdb TAP test with no TZ set

  3. Use one transaction while reading postgres.bki, not one per line.

  4. Move bootstrap-time lookup of regproc OIDs into genbki.pl.