Horton

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

Gavin Flower <gavinflower@archidevsys.co.nz>

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From: Gavin Flower <GavinFlower@archidevsys.co.nz>
To: Andreas Karlsson <andreas@proxel.se>, Tom Lane <tgl@sss.pgh.pa.us>, Andres Freund <andres@anarazel.de>
Cc: pgsql-hackers@postgresql.org
Date: 2017-04-15T02:08:39Z
Lists: pgsql-hackers 
On 15/04/17 13:44, Andreas Karlsson wrote:
> On 04/14/2017 11:54 PM, Tom Lane wrote:
>> I failed to resist the temptation to poke at this, and found that
>> indeed nothing seems to break if we just use one transaction for the
>> whole processing of postgres.bki.  So I've pushed a patch that does
>> that.  We're definitely down to the point where worrying about the
>> speed of bootstrap mode, per se, is useless; the other steps in
>> initdb visibly take a lot more time.
>
> Looked some at this and what take time now for me seems to mainly be 
> these four things (out of a total runtime of 560 ms).
>
> 1. setup_conversion:        140 ms
> 2. select_default_timezone:  90 ms
> 3. bootstrap_template1:      80 ms
> 4. setup_schema:             65 ms
>
> These four take up about two thirds of the total runtime, so it seems 
> likely that we may still have relatively low hanging fruit (but not 
> worth committing for PostgreSQL 10).
>
> I have not done profiling of these functions yet, so am not sure how 
> they best would be fixed but maybe setup_conversion could be converted 
> into bki entries to speed it up.
>
> Andreas
>
>
How much could be done concurrently?


Cheers.
Gavin

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.