On Wed, Jun 17, 2009 at 8:09 PM, Robert Haas<robertmhaas@gmail.com> wrote:
>
>> I have no idea what they are in Firebird but the name conjured up a
>> different (interesting) idea for me. I had the image of naming a
>> transaction and then being able to have other sessions join that same
>> transaction. We've discussed this before for connection-pooled systems
>> which want to be able to return their connection to the pool in the
>> middle of their transaction. It would also possibly be useful for
>> parallel data dumps and loads.
>
> At the risk of veering off-topic, wouldn't this present some awfully
> nasty issues vis-a-vis the command counter?
I didn't say it would be easy :)
I think the command counter might be ok (though I'm not sure we could
pull off the same "phantom cid" trick we do now). But locking and all
the per-transaction information stored in the pgproc info would be a
problem. Basically anywhere in the code where we used "session" as a
proxy for "transaction"...
--
greg
http://mit.edu/~gsstark/resume.pdf