I posted this in the JBoss forum's but came upon this more active Forum with respect to JUST hibernate. So here goes:

The default strategy is AUTO which according to the HibernateExt annotation processor dwindles into a "native" which eventually leads the EntityPersister handling these entities (such as the SingleTablePersister) to use the SequenceGenerator because the PostgresDialect's getNativeIdentiterGenerator returns this class (cool). Fine, but when the SequenceGenerator is configured, it creates a sequence called "hibernate_sequence" which is used to basically generate values (1,2,3 so on) for all tables....that does not seem kosher by any means....is this true?

It seems to me that if I have all my entities as AUTO then Hibernate should use create a per table, table_column_seq variable (SEQUENCE) to manage primary keys.

I've debugged this now over two days since Hibernate is new to me. Can someone who is knowledgeable with the source (and not dangerous like myself) comment on my observation? Is this really true?

I understand that a lot of folks are using @SequenceGenerator to solve some of this but I would much rather stay database agnostic and let my Persistence provider handle the details. For example, MySQL would not use sequences and instead use identity columns. Also, the problem with switching to using the @SequenceGenerator is I have existing tables and creating a sequence would flip it back to 1 which is no good.

I would really really appreciate any comments on the above issue.

And as such I forgot to mention the problem (dah):

The problem is that we have come across situations where Hibernate reuses a primary key that has been previous deleted (Entity was removed) which recycles the key generator causing exceptions.

So we have one Entity table that had 1,2,3 etc. till 43 and then 4 was deleted. Then we saw that a new Entity caused 4 to be reused so the next Entity is now 5 causing an EntityExists exception and the transaction fails. That's pretty much the pattern we see (this with the Hibernate shipped in JBoss404GA which I believe 3rc2 something or other - it flies by during deployment).

I decided to debug Hibernate itself and figure out exactly how it was determining what the next key is...etc...and stumbled across the above which I believe is the root of my problem.

Thanks again!

No one has seen this before? Does anyone use AUTO for postgres?

I use "native" for entity ID in PostgreSQL. It works for me. I don't think you shall use "auto" for your entity ID sequence.