Re: pgbench - allow to store select results into variables - Mailing list pgsql-hackers

From Pavel Stehule
Subject Re: pgbench - allow to store select results into variables
Date
Msg-id CAFj8pRAgU0OzGM7Vqpf2KUR0KP2YNhtG54ji06W5StGmwyQKnA@mail.gmail.com
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In response to pgbench - allow to store select results into variables  (Fabien COELHO <coelho@cri.ensmp.fr>)
Responses Re: pgbench - allow to store select results into variables  (Fabien COELHO <coelho@cri.ensmp.fr>)
List pgsql-hackers
Hi

2016-07-09 10:20 GMT+02:00 Fabien COELHO <coelho@cri.ensmp.fr>:

Hello devs,

I mentionned my intention to add some features to pgbench back in March:
https://www.postgresql.org/message-id/alpine.DEB.2.10.1603301618570.5677@sto

The attached patch adds an \into meta command to store results of preceding SELECTs into pgbench variables, so that they can be reused afterwards.

The feature is useful to make more realistic scripts, currently pgbench script cannot really interact with the database as results are discarded.

The chosen syntax is easy to understand and the implementation is quite light, with minimal impact on the code base. I think that this is a reasonnable compromise.

The SELECTs must yield exactly one row, the number of variables must be less than the number of columns.

Also attached a set of test scripts, especially to trigger various error cases.


Why you are introducing \into and not \gset like psql does?

Regards

Pavel
 
--
Fabien.


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