Re: Proposed patch: remove hard-coded limit MAX_ALLOCATED_DESCS

From: Cédric Villemain <cedric(at)2ndquadrant(dot)com>
To: pgsql-hackers(at)postgresql(dot)org
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Subject: Re: Proposed patch: remove hard-coded limit MAX_ALLOCATED_DESCS
Date: 2013-06-08 20:01:22
Message-ID: 201306082201.22931.cedric@2ndquadrant.com
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> > I just wonder about this statement that you removed:
> > * Since we don't want to encourage heavy use of those functions,
> > * it seems OK to put a pretty small maximum limit on the number of
> > * simultaneously allocated descs.
>
> > Is it now encouraged to use those functions, or at least that it seems less
> > 'scary' than in the past ?
>
> Well, we could put back some weaker form of the statement, but I wasn't
> sure how to word it.

I'm not sure of the 'expected' problems...
The only thing I can think of at the moment is the time spent to close
file descriptors on abort/commit.
I'm not sure of expected value of "max_safe_fds". Your patch now initialize
with 5 slots instead of 10, if max_safe_fds is large maybe it is better to
double the size each time we need instead of jumping directly to the largest
size ?

--
Cédric Villemain +33 (0)6 20 30 22 52
http://2ndQuadrant.fr/
PostgreSQL: Support 24x7 - Développement, Expertise et Formation

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