Ian Lance Taylor wrote: > [snip]
> > > > > > > > Yes TID is available and I introduced Tid Scan in order > > > > to support this kind of implementation. However there > > > > are some notices. > > > > 1) Is *FOR UPDATE* cursor allowed in PL/pgSQL ? > > > > (It doesn't seem easy for me). > > > > > > No, it is not supported right now. > > > > > > Conceptually, however, PL/pgSQL could pull out the FOR UPDATE clause > > > and turn it into an explicit LOCK statement. > > > > It's impossible to realize *FOR UPDATE* using LOCK statement. > > Each row must be locked individually to prevent UPDATE/DELETE > > operations for the row. You could acquire an EXCLUSIVE > > LOCK on the table but it doesn't seem preferable. > > It's definitely not preferable, but how else can it be done? > > > I'm planning to implement updatable cursors with no lock > > using TID and OID. TID is for the fast access and OID is > > to verify the identity. OID doesn't provide a specific > > access method in the first place and the access would be > > veeery slow for large tables unless there's an index on OID. > > I apologize if I've missed something, but how will that work when OIDs > become optional? > So I've objected optional OIDs. regards, Hiroshi Inoue ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster
