Re: SSI patch renumbered existing 2PC resource managers??

On 13.06.2011 22:33, Tom Lane wrote:
> Heikki Linnakangas<heikki(dot)linnakangas(at)enterprisedb(dot)com> writes:
>> On 13.06.2011 21:31, Tom Lane wrote:
>>> So far as I can tell, that breaks pg_upgrade (if there are any open
>>> prepared transactions) for no redeeming social benefit.
>
>> Surely pg_upgrade can't work anyway if there's any open prepared
>> transactions in the database. We're not going to guarantee to keep all
>> the data structures we write in two-phase state files unchanged over
>> major releases. If pg_upgrade is not checking for prepared transcations
>> at the moment, such a check should probably should be added.
>
> No, pg_upgrade should not be unilaterally refusing that. The correct
> way to deal with this consideration is to change the TWOPHASE_MAGIC
> number when we make a change in on-disk 2PC state. Which wasn't done
> in the SSI patch. We can either change that now, or undo the
> unnecessary change in existing RM IDs. I vote for the latter.

Ok, I've renumbered the existing RMs back the way they were.

I nevertheless don't think it's worthwhile to try to migrate 2pc state
files in pg_upgrade. More than likely, it's a mistake on part of the
admin anyway if there is a prepared transaction open at that point.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com