On Thu, Jun 29, 2006 at 14:27:30 +0200,
Martijn van Oosterhout wrote:
> On Thu, Jun 29, 2006 at 01:21:19PM +0100, Simon Riggs wrote:
> > The issue is the difference between start of transaction and time when
> > the serializable snapshot is taken. Since BEGIN and other commands may
> > be issued
"Tom Lane" <[EMAIL PROTECTED]> wrote
>
> It can, but there are cases where you want the lock to be taken before
> the snapshot is set. Otherwise, there could be committed changes in the
> database that you can't see in your snapshot. I think there are some
> examples in the manual, or check the
"Qingqing Zhou" <[EMAIL PROTECTED]> writes:
> "Tom Lane" <[EMAIL PROTECTED]> wrote
>> Right, the snapshot does not become set until you do a non-utility
>> command (normally, SELECT/INSERT/UPDATE/DELETE). This is a feature, not
>> a bug, because it lets the transaction take table locks before its
"Tom Lane" <[EMAIL PROTECTED]> wrote
>
> Right, the snapshot does not become set until you do a non-utility
> command (normally, SELECT/INSERT/UPDATE/DELETE). This is a feature, not
> a bug, because it lets the transaction take table locks before its
> snapshot becomes set.
>
Hm, mostly I unders
On Thu, 2006-06-29 at 14:27 +0200, Martijn van Oosterhout wrote:
> On Thu, Jun 29, 2006 at 01:21:19PM +0100, Simon Riggs wrote:
> > The issue is the difference between start of transaction and time when
> > the serializable snapshot is taken. Since BEGIN and other commands may
> > be issued as sepa
On Thu, Jun 29, 2006 at 01:21:19PM +0100, Simon Riggs wrote:
> The issue is the difference between start of transaction and time when
> the serializable snapshot is taken. Since BEGIN and other commands may
> be issued as separate network requests it makes sense to defer taking
> the snapshot until
On Wed, 2006-06-28 at 21:20 +0200, Martijn van Oosterhout wrote:
> 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:
>
>
>
> > http://www.postgresql.org/docs/8.1/in
Martijn van Oosterhout writes:
> 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.
Right, the
On Wed, Jun 28, 2006 at 14:48:01 -0400,
Brad Nicholson <[EMAIL PROTECTED]> wrote:
> I'm seeing something fairly unintuitive about serializable transactions.
>
> "When a transaction is on the serializable level, a SELECT query sees
> only data committed before the transaction began; it never sees
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:
> http://www.postgresql.org/docs/8.1/interactive/transaction-iso.html
>
> "When a transaction is on the serializable le
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