Tom Lane wrote:
>
> Philip Warner <pjw@rhyme.com.au> writes:
> >> The workaround for Forest is to make the final SELECT be a SELECT FOR
> >> UPDATE, so that it's playing by the same rules as the earlier commands.
>
> > Eek. Does this seem good to you?
>
> I did call it a workaround ;-)
>
> I don't think that we dare try to make any basic changes in MVCC for 7.1
> at this late hour, so Forest is going to have to live with that answer
> for awhile. But I would like to see a cleaner answer in future
> releases.
Is it the MVCC's restriction that each query inside a function
must use the same snapshot ?
> As I've opined before, the whole EvalPlanQual mechanism
> strikes me as essentially bogus in any case...
>
How would you change it ? UPDATE/SELECT FOR UPDATE have to
SELECT/UPDATE the latest tuples. I don't think of any simple
way for 'SELECT FOR UPDATE' to have the same visibility as
simple SELECT.
regards,
Hiroshi Inoue