Message-ID: <3DEF1C14.2000008@fibers.upc.es>
Date: Thu, 05 Dec 2002 10:27:48 +0100
From: Thrasher <thrasher@fibers.upc.es>
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To: "Berman, Phil" <PBerman@northropgrumman.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: Backend message type 0x50 arrived while idle
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Hi Phil

It also happened to me last week. I found the problem is that you cannot 
share the same connection among processes unless you implement some kind 
of locking (semaphores, ...).

More clearly, I had this problem.

Query QA lasts 5 seconds to perform, and returns answer AA.
Query QB lasts 10 seconds and returns AB.
B is a child process of A.

I launch the parent A. Performs QA. Waits for answer.
I launch the child B. Performs QB. Waits for answer.

Server returns AA, but it gets caught by B !!

So, solutions are:
	- You open a new backend connection for each process.
	- You make each process lock before sending QA, and unlock when 
receiving AA.

Hope it helps !!

Thrasher

Berman, Phil wrote:
> To all-
> I am using Postgres version 6.5.1 in a multithreaded program which is
> written in C.  All inserts and updates into any tables are done within the
> child process, and there are retrieves from tables both in the parent and
> child processes.  Additionally, the child process will insert into and
> update a table, and the parent process will retrieve from the same table.
> There are loops in both the parent and child processes, so every postgres
> call may be made multiple times, with a significant amount of time (seconds
> or minutes) between calls.  Invariably, I get a message "backend message
> type 0x50 arrived while idle" before the process completes, although the
> point where I get this message can vary somewhat.  Can anyone tell me what
> this message means, why I am getting it, and/or how to avoid getting it in
> the future?
> 
> Thanks in advance,
> Phil
> 
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