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Re: [Gnumed-devel] middleware upgrade
From: |
Karsten Hilbert |
Subject: |
Re: [Gnumed-devel] middleware upgrade |
Date: |
Sat, 24 Dec 2005 18:08:59 +0100 |
User-agent: |
Mutt/1.5.11 |
On Sat, Dec 24, 2005 at 09:41:24AM +0800, Syan Tan wrote:
> I was wondering if xmin checking was necessary if you had fine grained commit
> intervals;
That won't help any.
> so commit at every update
> when an item is changed or added in the gui view of the medical record,
Richard et al do not want that.
> then reopen a transaction for the next commit. this would mean
> a user who has a too-late update due to another user earlier updating the same
> item and committng, will be notified with a transaction
> abort.
No, why ? Transactions only ensure all-or-nothing, eg the
atomicity of an action. They are not at all concerned about
the *content*. To detect intermittent content changes we
need xmin. Another possibility would be to lock the tables
right from the beginning but we don't want that.
Karsten
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