Re: OT: Question about transactions

On Tue, Aug 12, 2008 at 1:09 PM, Paul Tomblin <ptomblin(at)gmail(dot)com> wrote:

> is there a way for the other JVMs to get a consistent view
> of the database?

My understanding is that PostgreSQL only supports two forms of
transaction Isolation: READ COMMITED AND SERIALIZABLE. This means
that only the client that has opened the transaction can see
un-commited data. All other client instances will see only the
commited data.

> For instance, if program 1 updates something in the
> database and commits, and then tells everybody that's it's updated,
> and then deletes the item from the database and commits, and then
> tells everybody that it's deleted,

I'm not to sure on this one. If the other JVM are using a seperate
connection, I wouldn't expect you to be able to achieve consistant
results. However, maybe postgreSQL's LISTEN and NOTIFY will do what
you need?
http://www.postgresql.org/docs/8.3/interactive/sql-listen.html
http://www.postgresql.org/docs/8.3/interactive/sql-notify.html

--
Regards,
Richard Broersma Jr.

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