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From: Bruce Momjian <pgman@candle.pha.pa.us>
Message-Id: <200312160108.hBG18i511422@candle.pha.pa.us>
Subject: Re: Possible bug in ECPGlib thread-safety (Postgres
In-Reply-To: <Pine.LNX.4.44.0312042302230.11170-100000@ser1.cpc.net.au>
To: Philip Yarra <philip@utiba.com>
Date: Mon, 15 Dec 2003 20:08:44 -0500 (EST)
Cc: Demetres Pantermalis <dpant@intracom.gr>, pgsql-interfaces@postgresql.org
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I have updated the 7.4.X does and CVS head docs to mention that ecpg SET
CONNECTION is not thread-aware, and I have added this to the ecpg TODO:

        o Make SET CONNECTION thread-aware

---------------------------------------------------------------------------

Philip Yarra wrote:
> Hi Demetres, I'm the guy whose emails you quoted below! 
> 
> You *must* always use the AT conn_name in a multi-threaded application... 
> using SET CONNECTION will not work.
> 
> I assume your test results work if you use the thread test application as 
> included (I wrote it, so I'd be interested to know if it works, as I have 
> not tested RH9 and SunOS5.8 (though I tested RH7.3 and SunOS2.6)
> 
> Regards, Philip Yarra.
> 
> On Thu, 4 Dec 2003, Demetres Pantermalis wrote:
> 
> > Dear All,
> > 
> > trying to run some tests for the thread-safety of the ecpg library, I
> > modified the test_thread.pgc to be like the one attached (test_thread1.pgc).
> > 
> > The changes are as follows:
> > 1) All the connections used for insertions, begin in main function (and not
> > inside each thread)
> > 2) The statement "EXEC SQL SET CONNECTION <conn> followed by the inserts is
> > used, instead of the"EXEC SQL AT <conn> ..." statement.
> > 3) A new line for ECPGlog was added.
> > 
> > The results of executing the code are unexpected. Either a core dump
> > results, or one of the two threads inserts the rows in the table and the
> > process never returns to OS prompt, while the other thread seems to insert
> > the rows, but never commits.
> > 
> > A log file produced by ECPGlog is also attached.
> > 
> > Platforms tested: SunOS 5.8 and Linux RH9 (with the same results)
> > 
> > Any suggestions appreciated.
> > 
> > PS. I've found out that somebody else had about the same problem, but that
> > was during testing phase and I assumed that it could have been solved by
> > now. The links found are:
> > http://archives.postgresql.org/pgsql-hackers/2003-06/msg00513.php
> > http://archives.postgresql.org/pgsql-hackers/2003-06/msg00792.php
> > 
> > Demetres Pantermalis
> > Intracom SA
> > Network Support Systems.
> > 
> 
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Don't 'kill -9' the postmaster
> 

-- 
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