From: Tom Lane <tgl@sss.pgh.pa.us>
To: Craig Brozefsky <craig@red-bean.com>
Cc: pgsql-interfaces@postgresql.org
Subject: Re: issues with libpg interface
Date: Wed, 17 Jan 2001 20:55:28 -0500
Message-ID: <22568.979782928@sss.pgh.pa.us> (raw)
In-Reply-To: <87itndwy8n.fsf@piracy.red-bean.com>
References: <87itndwy8n.fsf@piracy.red-bean.com>
Craig Brozefsky <craig@red-bean.com> writes:
> We have two situations that have arisen while using libpq thru CMUCL
> bindings in our UncommonSQL package. We have a multi-processing
> application which uses a pool of database connections to perform DB
> queries.
> The first one is that we are getting unexpected retun values from
> pgresultstatus after calling pgexec, a value of PGRES_TUPLES_OK. The
> thing is that we're not sending a SELECT, just UPDATES, INSERTS and
> DELETES. My understanding is that none of those return tuples.
They don't. I think you must have some kind of multithreading bug
on the client side (whether it's in libpq or your code is hard to say).
A quick look at libpq's source shows that it can only generate
PGRES_TUPLES_OK after seeing a 'T' (row descriptor) message from the
backend, and the backend will surely not send such a thing except for
SELECT or FETCH.
> Also, unrelated, I think, to the above issue, we are getting the
> following message intermittently:
> Backend message type 0x50 arrived while idle
That would be a 'P' (CursorResponse) message, which is a normal (if
not very useful) part of the query cycle. Something's definitely
out of sync in the frontend/backend protocol, it seems. You might
find it helpful to read
http://www.postgresql.org/devel-corner/docs/postgres/protocol.htm
regards, tom lane
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To: pgsql-interfaces@postgresql.org
Cc: tgl@sss.pgh.pa.us, craig@red-bean.com
Subject: Re: issues with libpg interface
In-Reply-To: <22568.979782928@sss.pgh.pa.us>
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