Re: psql FETCH_COUNT feature does not work with combined queries

On Fri, Jul 26, 2019 at 04:13:23PM +0000, Fabien COELHO wrote:
>
>>FETCH_COUNT does not work with combined queries, and probably has 
>>never worked since 2006.
>
>For the record, this bug has already been reported & discussed by 
>Daniel Vérité a few months back, see:
>
>https://www.postgresql.org/message-id/flat/a0a854b6-563c-4a11-bf1c-d6c6f924004d%40manitou-mail.org
>
>Given the points of view expressed on this thread, especially Tom's 
>view against improving the lexer used by psql to known where query 
>ends, it looks that my documentation patch is the way to go in the 
>short term, and that if the "always show query results" patch is 
>committed, it might simplify a bit solving this issue as the PQexec 
>call is turned into PQsendQuery.
>

Assuming there's no one willing to fix the behavior (and that seems
unlikely given we're in the middle of a 2020-01 commitfest) it makes
sense to at least document the behavior.

That being said, I think the proposed patch may be a tad too brief. I
don't think we need to describe the exact behavior, of course, but maybe
it'd be good to mention that the behavior depends on the type of the
last command etc. Also, I don't think "combined query" is a term used
anywhere in the code/docs - I think the proper term is "multi-query
string".


regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
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