Re: support for hyper-long transactions ...

Hans-Juergen Schoenig wrote:
> at the moment i am working on an application which is supposed to run
> extremely large transactions (a lot of server side stored procedure
> stuff which can hardly be split into small transactions for visibility
> reasons).
> so, from time to time it happens that i exceed my CommandCounter (>
> 2.000.000.000 statements inside the same transaction).

Interesting. What kind of a stored procedure is that?

One optimization that might be possible is to not increment it for
statements that do on-disk changes.

> my idea is: how about adding a configure option to compile postgres with
> a 64 bit command counter. this would allow larger transactions for
> special purpose applications while it would not have an impact on normal
> applications.

One objection to expanding TransactionId to 64-bits has been that we
depend on assignment of TransactionId to be atomic. That might not be an
issue with CommandIds; I don't think we store commandids in shared
memory structures. It still doesn't feel like a good idea to me, though.

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