Horton

Re: pgbench - allow to store select results into variables

Tom Lane <tgl@sss.pgh.pa.us>

View thread View on postgr.es
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>
Date: 2016-07-13T20:26:12Z
Lists: pgsql-hackers 
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

Commits

  1. pgbench: Remove \cset

  2. pgbench: add \cset and \gset commands

  3. Adjust pgbench to allow non-ASCII characters in variable names.

  4. Refactor script execution state machine in pgbench.

  5. Allow empty queries in pgbench.