Re: User-facing aspects of serializable transactions

Kevin,

> I'm not sure it's without value to the project; I just don't know that
> it would be worth using for us.  It seems to be accepted in some other
> DBMS products.  Since some (like MS SQL Server) allow users to choose
> snapshot isolation or blocking-based serializable transactions in
> their MVCC implementation, it would be interesting to know how many
> users have chosen the latter.  Has anyone seen numbers (or even have
> anecdotal evidence) on this point?

This approach allowed MSSQL to "clean up" on TPCE; to date their 
performance on that benchmark is so much better than anyone else nobody 
else wants to publish.

So, at least theoretically, anyone who had a traffic mix similar to TPCE 
would benefit.  Particularly, some long-running serializable 
transactions thrown into a mix of Read Committed and Repeatable Read 
transactions, for a stored procedure driven application.

In the field, we're not going so see a lot of requests for this because 
most applications that complex run in Java middleware with pessimistic 
locking.  To the exent, though, that we want to promote PostgreSQL as 
'better development platform' for transactional applications, it might 
be beneficial to support more sophisticated serializablity.

Besides, I'd love to beat Microsoft on TPCE.  ;-)

-- 
Josh Berkus
PostgreSQL Experts Inc.
www.pgexperts.com