From: Michael Meskes <meskes@postgresql.org>
To: pgsql-interfaces@postgresql.org
Subject: Re: [HACKERS] ECPG ignores SAVEPOINT if first statement of a
	transaction
Date: Fri, 26 Aug 2005 15:09:11 +0200
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Cc: Michael Fuhr <mike@fuhr.org>,
	Bruce Momjian <pgman@candle.pha.pa.us>
References: <20050803153223.GA17861@winnie.fuhr.org>
	<200508130222.j7D2MWh29185@candle.pha.pa.us>
	<20050813150145.GA87926@winnie.fuhr.org>
In-Reply-To: <20050813150145.GA87926@winnie.fuhr.org>
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Am Samstag, 13. August 2005 17:01 schrieb Michael Fuhr:
> On Fri, Aug 12, 2005 at 10:22:32PM -0400, Bruce Momjian wrote:
> > Michael Fuhr wrote:
> > > ECPG ignores SAVEPOINT if it's the first statement of a transaction:
> 
> ECPGtrans() ignores the statement because of this check:
>
>   /*
>    * if we are not in autocommit mode, already have committed the
>    * transaction and get another commit, just ignore it
>    */
>   if (!con->committed || con->autocommit)
>   {
>           if ((res = PQexec(con->connection, transaction)) == NULL)
>           {
>                   ECPGraise(lineno, ECPG_TRANS,
> ECPG_SQLSTATE_TRANSACTION_RESOLUTION_UNKNOWN, NULL); return FALSE;
>           }
>           PQclear(res);
>   }
>
> If no statements have been executed in this transaction then committed
> is true, so ECPGtrans() ignores the current statement.  It looks

I have to admit that this code is so old I have to think quite a bit about why 
it is done this way.

> like the code should make an extra consideration for SAVEPOINT in
> case it's the first statement.

Yes, I agree.

> I'm also wondering if the check for a NULL return value from PQexec()
> is sufficient.  Shouldn't it also check for a non-NULL result that's
> anything other than PGRES_COMMAND_OK?

Seems to make sense too. The NULL return value would just mean that the 
statement wasn't even started. If it is but returns an error, it is 
considered valid here, right?

Michael
-- 
Michael Meskes
Email: Michael at Fam-Meskes dot De, Michael at Meskes dot (De|Com|Net|Org)
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