Re: Migration to Hibernate 3.5 final

Hi,

I shuold give few words of explanation, which I didn't wrote because of
tragedy that was on 10th Apr in Smolensk.

This generaly isn't bug in PG JDBC, but change of default implementation of
Hibernate in 3.5 version (it should not happen, because some old legacy
application, without support or source code can't be migrated to Hibernate 3.5
and so to J2EE6). In my situation setting compatible property on connection
didn't helped.

Much more this what I saw in 3.5 - beta 2, and i don't know if this was fixed
is Hibernate - without @Type annotation - will auto-create column of type oid
(correct!) , but will try to read this as bytea (SIC!)

Dnia poniedziałek 12 kwiecień 2010 o 13:45:49 Rafael Felix napisał(a):
> Radoslaw and Craig,
>
> Thanks for ansewers, the @Type annotations was worked for me.
>
> About the Craig questions, I'm using the literal oid field.
>
> Thanks for all
>
> regards
>
> Em 10/4/2010 09:58, Radosław Smogura escreveu:
> > I had similar problems, try use on byte[] field following Hibernate
> > annotation @Type(type="org.hibernate.type.PrimitiveByteArrayBlobType")
> >
> > Dnia sobota 10 kwiecień 2010 o 13:36:42 Craig Ringer napisał(a):
> >> Rafael Felix wrote:
> >>> I´ve an application running in hibernate 3.3.2 and the applications
> >>> works fine, with all blob fields using oid (byte[] in java),
> >>
> >> Do you mean you're using the literal type `oid' in the Pg fields? Or are
> >> you using the `lo' contrib type?
> >>
> >> By using the `oid' type you're using out-of-line large objects,
> >> referenced by object id (oid).
> >>
> >> If you use `oid' directly, then when you delete a row from your table
> >> the corresponding large object will NOT be deleted. The `lo' wrapper
> >> contrib type provides that. It's not in mainline yet (alas), perhaps
> >> because it can't guarantee correctness - in particular a TRUNCATE TABLE
> >> will still leak large objects.
> >>
> >>> Migrating to hibernate 3.5 all blob fields not work anymore, and the
> >>> server log shows
> >>>
> >>> ERROR org.hibernate.util.JDBCExceptionReporter - ERROR: column
> >>> "preferencia" is of type oid but expression is of type bytea
> >>
> >> OK, so you're now mapping byte[] to the Pg type 'bytea' instead of to pg
> >> large objects.
> >>
> >> You can change this mapping in your hibernate settings if you want
> >> things to go back to how they were. See large object mapping in the
> >> Hibernate documentation.
> >>
> >>> But I'm cann't change the tables struct for use bytea instead oid,
> >>> because I lost all data.
> >>
> >> Do you mean "because you've lost all your data" or "because by doing so
> >> you will lose all your data"?
> >>
> >> I presume the latter.
> >>
> >> What I'd do would be:
> >>
> >> a) Change hibernate's mapping for byte[] back to large object instead of
> >> bytea by overriding it in the Hibernate configuration
> >>
> >> b) Evaluate whether bytea or large object is actually better for you by
> >> reading the postgresql documentation and thinking a about your needs.
> >> Consider how often you update the data, how big the maximum size of
> >> object you need to store is, etc.
> >>
> >> c) Decide whether you should migrate to bytea or stick with large
> >> objects.
> >>
> >> d) If you stick to large objects, switch from raw oid types to `lo'
> >> types, so you get proper large object cleanup on delete/update. Consider
> >> using vacuumlo .
> >>
> >> --
> >> Craig Ringer
>