Received: from magus.postgresql.org (magus.postgresql.org [87.238.57.229])
	by mail.postgresql.org (Postfix) with ESMTP id 5981116AF4E5
	for <pgsql-admin@postgresql.org>; Mon, 30 Jul 2012 10:53:26 -0300 (ADT)
Received: from sss.pgh.pa.us ([66.207.139.130])
	by magus.postgresql.org with esmtp (Exim 4.72)
	(envelope-from <tgl@sss.pgh.pa.us>) id 1SvqPS-0001Qo-W0
	for pgsql-admin@postgresql.org; Mon, 30 Jul 2012 13:53:25 +0000
Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1])
	by sss.pgh.pa.us (8.14.5/8.14.5) with ESMTP id q6UDr5Rn027774;
	Mon, 30 Jul 2012 09:53:05 -0400 (EDT)
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Amit Kumar <helloamit5@gmail.com>
cc: pgsql-admin@postgresql.org, amit.jain@netcore.co.in
Subject: Re: Sometime Update is not modifying data inside database.
In-reply-to: 
 <CAJ6=GOfS96oEjkV-VpnyFKTJXuWYaySj+WtY-jHVmPg0X1Nk+g@mail.gmail.com>
References: 
 <CAJ6=GOfS96oEjkV-VpnyFKTJXuWYaySj+WtY-jHVmPg0X1Nk+g@mail.gmail.com>
Comments: In-reply-to Amit Kumar <helloamit5@gmail.com>
	message dated "Mon, 30 Jul 2012 16:36:54 +0530"
Date: Mon, 30 Jul 2012 09:53:05 -0400
Message-ID: <27773.1343656385@sss.pgh.pa.us>
X-Pg-Spam-Score: -1.9 (-)
X-Archive-Number: 201207/102
X-Sequence-Number: 39819

Amit Kumar <helloamit5@gmail.com> writes:
> <snip>
> Jul 30 12:40:36 dell16 postgres[11088]: [11-1] 2012-07-30 12:40:36 IST
> [11088]: [10-1] user=postgres,db=dbpush xxxxxxxxxxxxxxxxxx(43225)LOG:
> statement: START TRANSACTION
> Jul 30 12:40:36 dell16 postgres[11088]: [12-1] 2012-07-30 12:40:36 IST
> [11088]: [11-1] user=postgres,db=dbpush xxxxxxxxxxxxxxxxxx(43225)LOG:
> statement: *UPDATE dbpush_camp_main SET status=7 WHERE camp_id IN(137721)*
> Jul 30 12:40:36 dell16 postgres[11088]: [13-1] 2012-07-30 12:40:36 IST
> [11088]: [12-1] user=postgres,db=dbpush xxxxxxxxxxxxxxxxxx(43225)LOG:
> statement: COMMIT
> Jul 30 12:40:36 dell16 postgres[9368]: [5-1] 2012-07-30 12:40:36 IST
> [9368]: [4-1] user=postgres,db=dbpush xxxxxxxxxxxxxxxxxx(43187)LOG:
> statement: SELECT status FROM  dbpush_camp_main  WHERE camp_id=137721
> </snip>

I assume what you're complaining about is that PID 9368's select didn't
see the result of pid 11088's update?  The above trace doesn't prove
that anything is wrong.  That behavior would be expected if 9368 had
taken its "snapshot" before 11088's commit finished, and you can't
really tell if that was the case or not from these log entries.  But
given they all happened in less than 1 second, it's certainly possible.

			regards, tom lane