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

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