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Re: VIP: new format for psql - shell - simple using psql in shell

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>,PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: VIP: new format for psql - shell - simple using psql in shell
Date: 2012-05-26 17:24:47
Message-ID: 20120526172447.GD23645@momjian.us (view raw or flat)
Thread:
Lists: pgsql-hackers
On Sat, May 26, 2012 at 12:43:40PM -0400, Tom Lane wrote:
> Bruce Momjian <bruce(at)momjian(dot)us> writes:
> > On Sat, May 26, 2012 at 05:39:23PM +0200, Pavel Stehule wrote:
> >> I proposed new psql's format "shell". This format is optimized for
> >> processing returned result in shell:
> 
> > I am unclear exactly how this relates to shells.
> 
> What I'm unclear on is why we'd want to encourage that style of
> programming.  The most charitable prediction of performance is that it
> would suck --- not only do you have all the inefficiencies inherent in
> row-by-row result processing with a shell script, but you're forcing a
> separate database connection for each query.  And I don't actually see
> where it would be especially convenient to use, compared to say perl
> or python or other scripting languages.  I'd rather see us worrying
> about the convenience of cases like

Wouldn't you just us unaligned mode for this, and set IFS  to '|'?

	$ psql --no-align --tuples-only -c 'SELECT 1,2' test
	1|2

	$ export IFS="|"
	$ IFS='|' sql --no-align --tuples-only -c 'SELECT 1,2' test | 
	while read x y; do echo $x; echo $y; done
	1
	2

Are you worried about pipes in data?  Does you idea fix this?

-- 
  Bruce Momjian  <bruce(at)momjian(dot)us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + It's impossible for everything to be true. +

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Subject: Re: Backends stalled in 'startup' state: index corruption
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Subject: Re: VIP: new format for psql - shell - simple using psql in shell

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