Re: [HACKERS] SPI procedure for removing large objects

On Wed, 5 Aug 1998, David Hartwig wrote:

>
>
> Peter T Mount wrote:
>
> > On Wed, 5 Aug 1998, Bruce Momjian wrote:
> >
> > > > Peter,
> > > >
> > > > I have just finished up some other stuff in the backend, and I was
> > > > wondering what to do next.   My personal list include a cleanup of the lo
> > > > type.  Specifically:
> > > >
> > > >     1.  Assign a fixed OID to the LO type so that attributes of this type
> > > > can easily be identified.
> > > >
> > > >     2.  Write a VACUUM  LO procedure.
> > > >
> > > >     3.  Extend/verify the existing internal lo functions to work with the
> > > > new type.
> > > >
> > > > I know that more can/should be done in this area, but I only have so much
> > > > time.  I am aware the you have done some work on this in the contrib area.
> > > > Were you planning on handling any (or all) of these issues as part of the
> > > > 6.4 base release?   I will gladly move on to something else.
> > > >
> > >
> > > We should also make a large object type, rather than using inv_ to
> > > identify it.  It is on the TODO list, and I can implement it whenever
> > > you want.
> >
> > agreed - although that would imply a different method of storing them. One
> > of the problems I have with VACUUM LO is that using the existing oid
> > method (for compatibility) would not work with the new type.
> >
>
> I see it that way also.   But I do not perceive this to be a problem.   Users who
> have been using OIDs to link to their large_objects will continue to operate as
> they always have.   I can't see how we could attempt to promote the functionality
> of existing install base.   The problem, which is the essential problem, is that
> we can presume nothing about the relationship between an arbitrary OID type column
> and the large objects themselves.

Actually, if what Bruce is saying about LO then this problem may go away.

> However as part of a conversion, the DBA may be able to UPDATE pg_attribute
> manually and  change the type from OID to LO.  ???  Or we provide a script to do
> this where the DBA enters the large object columns???

I don't think it would hurt to have a script to to the conversion -
especially for those who are upgrading existing databases.

> > Either using a different form of storage, or a different prefix would sort
> > this problem (the latter would be the easiest).
> >

--
Peter T Mount peter@retep.org.uk or petermount@earthling.net
Main Homepage: http://www.retep.org.uk
PostgreSQL JDBC Faq: http://www.retep.org.uk/postgres