Re: [PERFORM] Concurrency issue under very heay loads

From: "ramasubramanian" <ramasubramanian(dot)g(at)renaissance-it(dot)com>
To: "Raji Sridar \(raji\)" <raji(at)cisco(dot)com>, <pgsql-general(at)postgresql(dot)org>, <pgsql-performance(at)postgresql(dot)org>
Subject: Re: [PERFORM] Concurrency issue under very heay loads
Date: 2009-07-16 05:19:17
Message-ID: 28022EE0B1F94CE59A0C270DE78D4571@ramasubramanian
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Hi,
Are you using automatic sequence increment in table?
----- Original Message -----
From: Raji Sridar (raji)
To: pgsql-general(at)postgresql(dot)org ; pgsql-performance(at)postgresql(dot)org
Sent: Thursday, July 16, 2009 10:29 AM
Subject: [PERFORM] Concurrency issue under very heay loads

Hi,

We use a typical counter within a transaction to generate order sequence number and update the next sequence number. This is a simple next counter - nothing fancy about it. When multiple clients are concurrently accessing this table and updating it, under extermely heavy loads in the system (stress testing), we find that the same order number is being generated for multiple clients. Could this be a bug? Is there a workaround? Please let me know.

Thanks
Raji

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