Skip site navigation (1) Skip section navigation (2)

Re: [PERFORM] psql -A (unaligned format) eats too much

From: "Mark Woodward" <pgsql(at)mohawksoft(dot)com>
To: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: "Jim C(dot) Nasby" <jnasby(at)pervasive(dot)com>, "Zoltan Boszormenyi" <zboszor(at)dunaweb(dot)hu>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: [PERFORM] psql -A (unaligned format) eats too much
Date: 2006-06-05 16:48:12
Message-ID: 18006.24.91.171.78.1149526092.squirrel@mail.mohawksoft.com (view raw or flat)
Thread:
Lists: pgsql-hackerspgsql-performance
> "Jim C. Nasby" <jnasby(at)pervasive(dot)com> writes:
>> On Mon, Jun 05, 2006 at 11:27:30AM -0400, Tom Lane wrote:
>>> I'm reading this as just another uninformed complaint about libpq's
>>> habit of buffering the whole query result.  It's possible that there's
>>> a memory leak in the -A path specifically, but nothing said so far
>>> provided any evidence for that.
>
>> Certainly seems like it. It seems like it would be good to allow for
>> libpq not to buffer, since there's cases where it's not needed...
>
> See past discussions.  The problem is that libpq's API says that when it
> hands you back the completed query result, the command is complete and
> guaranteed not to fail later.  A streaming interface could not make that
> guarantee, so it's not a transparent substitution.
>
> I wouldn't have any strong objection to providing a separate API that
> operates in a streaming fashion, but defining it is something no one's
> bothered to do yet.  In practice, if you have to code to a variant API,
> it's not that much more trouble to use a cursor...
>

Wouldn't the "COPY (select ...) TO STDOUT" format being discussed solve
this for free?

In response to

Responses

pgsql-performance by date

Next:From: Mark WoodwardDate: 2006-06-05 17:01:45
Subject: Re: [PERFORM] psql -A (unaligned format) eats too much
Previous:From: Zoltan BoszormenyiDate: 2006-06-05 16:45:13
Subject: Re: [PERFORM] psql -A (unaligned format) eats too much

pgsql-hackers by date

Next:From: Zdenek KotalaDate: 2006-06-05 16:55:50
Subject: Re: Allow commenting of variables in postgresql.conf to -
Previous:From: Zoltan BoszormenyiDate: 2006-06-05 16:45:13
Subject: Re: [PERFORM] psql -A (unaligned format) eats too much

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group