> Tom Lane wrote:
> >
> > Hiroshi Inoue <Inoue@tpf.co.jp> writes:
> >
> > > For example is it possible to update a toast
> > > chunk partially using SnapshotToast ?
> >
> > As things stand (with either SnapshotToast or the old SnapshotAny way)
> > it is never possible to update an individual toast value, either
> > partially or wholly. All you can do is lay down a new toast value (with
> > a new identifying OID) and then delete the old one.
> >
> > But I'm not sure that this is wrong, or fixable. Trying to update part
> > of a toasted value is very much like wanting to update part of an
> > existing row in-place, which we cannot possibly do.
>
> Bytea seems to be considered as a candidate for BLOB
> though I think the entirely new type is preferable.
> It seems impossible to implement a functionality like
> inv_write using bytea which the current large object
> stuff has.
Agreed. I think that was the reason we kept TOAST and large objects,
because large objects were designed for random read-write. If we can
get large objects to auto-delete, probably with pg_depend, we can then
use them seamlessly with BLOB I/O routines.
-- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610)
853-3000+ If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill,
Pennsylvania19026
