From: Tom Lane <tgl@sss.pgh.pa.us>
To: Fabien COELHO <coelho@cri.ensmp.fr>
cc: Robert Haas <robertmhaas@gmail.com>,
        Pavel Stehule <pavel.stehule@gmail.com>,
        PostgreSQL Developers <pgsql-hackers@postgresql.org>
Subject: Re: pgbench - allow to store select results into variables
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Comments: In-reply-to Fabien COELHO <coelho@cri.ensmp.fr>
	message dated "Wed, 13 Jul 2016 22:16:25 +0200"
Date: Wed, 13 Jul 2016 16:26:12 -0400
Message-ID: <572.1468441572@sss.pgh.pa.us>
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Fabien COELHO <coelho@cri.ensmp.fr> writes:
> Sending a batch of requests is a feature of libpq which is accessible 
> through pgbench by using "\;", although the fact is not documented. It 
> makes sense for a client to send independent queries together so as to 
> reduce latency.

You're putting an awful lot of weight on an unsupported assertion about
latency.  If a user cares about that, why would she not simply merge the
commands into "SELECT 1, 2, 3 \into one two three" ?

And I still say that what you're proposing might be easy right now, but
it might also be next door to impossible in a refactored implementation.
I don't think we should go there on the basis of a weak argument about
latency.  \into should retrieve data only from the last PGresult.

			regards, tom lane


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