Re: [BUGS] BUG #2129: dblink problem

From: Joe Conway <mail(at)joeconway(dot)com>
To: "Patches (PostgreSQL)" <pgsql-patches(at)postgresql(dot)org>
Cc: Akio Iwaasa <iwaasa(at)mxs(dot)nes(dot)nec(dot)co(dot)jp>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Subject: Re: [BUGS] BUG #2129: dblink problem
Date: 2006-01-03 05:09:29
Message-ID: 43BA0709.5010106@joeconway.com
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Joe Conway wrote:
> However, there is a remaining oddity with dblink_fetch(). Basically,
> each time dblink_fetch() is called, the named cursor is advanced, even
> though an error is thrown before returning any rows. Is there a simple
> way to get the number of columns in the result, without actually
> advancing the cursor?

I thought I could work around this issue by obtaining the count returned
for the FETCH using PQcmdTuples(), and then issuing a "MOVE BACWARD
n..." in the case where the return tuple doesn't match. However I get an
empty string:

(gdb) p str->data
$34 = 0x8a4e5a8 "FETCH 2 FROM rmt_foo_cursor"
(gdb) p PQcmdStatus(res)
$35 = 0x8a447c8 "FETCH"
(gdb) p PQcmdTuples(res)
$36 = 0x29dada ""

Any ideas why this isn't working?

Thanks,

Joe

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