Re: pgbench doc fix

From: Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr>
To: Tatsuo Ishii <ishii(at)sraoss(dot)co(dot)jp>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: pgbench doc fix
Date: 2018-10-30 08:57:09
Message-ID: alpine.DEB.2.21.1810300927540.9086@lancre
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Hello Tatsuo-san,

> pgbench doc (and some comments in pgbench.c) regarding "-M prepared"
> option is not quite correct. [...] Actually "extended" mode uses
> prepared statements too.

Ok, I understand that you mean that PQsendQueryParams uses an unamed query
internally to separate parsing & execution, which seems indeed to be the
case by looking at the libpq client-side code.

However, if I'm not mistaken, the params version always sends and possibly
reparses the query each time (is there a server side cache to avoid
re-parsing? a quick scan in the sources did not return a clear answer to
this question, but I think to recall that the answer is yes).

> Patch attached.

Patch applies cleanly, compiles, doc generation ok, global & local tests
are ok.

I'm fine having a more precise wording.

Maybe I would have also insisted on the fact that there is an explicit vs
an implicit PREPARE, if it relies on a server-side cache. The "extended"
documentation entry does not say that it is prepared.

I created an entry in the CF and marked the patch as ready anyway.


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