Re: plpgsql function with update and seeing changed data from outside during run

2011/6/9 Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>:
> Merlin Moncure <mmoncure(at)gmail(dot)com> writes:
>> On Thu, Jun 9, 2011 at 4:46 AM, Craig Ringer
>> <craig(at)postnewspapers(dot)com(dot)au> wrote:
>>> (as far as I know) It's not possible for a function to see data committed by
>>> other transactions since that function began executing, whether or not those
>>> other transactions have committed.
>
>> This is not correct. Yes, a snapshot is created, but that doesn't
>> prevent you from seeing external changes.  I have in fact many times
>> relied on being able to block in a pl/pgsql loop and wait for a record
>> to be set or something like that.
>
> Note that the function needs to be declared VOLATILE for that to work.
>
> But I believe the OP's question was the other way around: he wanted to
> be able to see changes made by a function from elsewhere, before the
> function completes.  That's not possible, unless you resort to hacks
> like using dblink to get the effect of autonomous subtransactions.

Thanks, seems my only way would be to try dblink then.

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