Re: Strange Behavior with Serializable Transcations - Mailing list pgsql-general

From Martijn van Oosterhout
Subject Re: Strange Behavior with Serializable Transcations
Date
Msg-id 20060628192049.GA6760@svana.org
Whole thread Raw
In response to Strange Behavior with Serializable Transcations  (Brad Nicholson <bnichols@ca.afilias.info>)
Responses Re: Strange Behavior with Serializable Transcations
Re: Strange Behavior with Serializable Transcations
List pgsql-general
On Wed, Jun 28, 2006 at 02:48:01PM -0400, Brad Nicholson wrote:
> I'm seeing something fairly unintuitive about serializable transactions.
>
> Taking the following test case:

<snip>

> http://www.postgresql.org/docs/8.1/interactive/transaction-iso.html
>
> "When a transaction is on the serializable level, a SELECT query sees
> only data committed before the transaction began; it never sees either
> uncommitted data or changes committed during transaction execution by
> concurrent transactions."

I think the issue here is that transaction begin is not when you type
"begin" but at your first actual query. You can obviously only start a
transaction once you know what serialisation level you want, and you
don't see that till after the begin.

Hope this helps,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.

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