From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andreas Karlsson <andreas@proxel.se>
cc: pgsql-hackers@postgreSQL.org, Andres Freund <andres@anarazel.de>
Subject: Re: Cutting initdb's runtime (Perl question embedded)
In-reply-to: <972d541d-7285-53ff-ea71-dcbfd886570a@proxel.se>
References: <30896.1492006367@sss.pgh.pa.us>
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 <972d541d-7285-53ff-ea71-dcbfd886570a@proxel.se>
Comments: In-reply-to Andreas Karlsson <andreas@proxel.se>
	message dated "Wed, 12 Apr 2017 21:15:53 +0200"
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Date: Thu, 13 Apr 2017 12:13:30 -0400
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Andreas Karlsson <andreas@proxel.se> writes:
> Here is my proof of concept patch. It does basically the same thing as 
> Andres's patch except that it handles quoted values a bit better and 
> does not try to support anything other than the regproc type.

> The patch speeds up initdb without fsync from 0.80 seconds to 0.55 
> seconds, which is a nice speedup, while adding a negligible amount of 
> extra work on compilation.

I've pushed this with some mostly-cosmetic adjustments:

* created a single subroutine that understands how to split DATA lines,
rather than having several copies of the regex

* rearranged the code so that the data structure returned by
Catalog::Catalogs() isn't scribbled on (which was already
happening before your patch, but it seemed pretty ugly to me)

* stripped out the bootstrap-time name lookup code from all of reg*
not just regproc.

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.

			regards, tom lane


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