On Tue, Jan 18, 2011 at 12:23 PM, Jim Nasby <j...@nasby.net> wrote: > On Jan 17, 2011, at 8:11 PM, Robert Haas wrote: >> On Mon, Jan 17, 2011 at 7:56 PM, Jim Nasby <j...@nasby.net> wrote: >>> - Forks are very possibly a more efficient way to deal with TOAST than >>> having separate tables. There's a fair amount of overhead we pay for the >>> current setup. >> >> That seems like an interesting idea, but I actually don't see why it >> would be any more efficient, and it seems like you'd end up >> reinventing things like vacuum and free space map management. > > The FSM would take some effort, but I don't think vacuum would be that hard > to deal with; you'd just have to free up the space in any referenced toast > forks at the same time that you vacuumed the heap.
How's that different from what vacuum does on a TOAST table now? >>> - Dynamic forks would make it possible to do a column-store database, or at >>> least something approximating one. >> >> I've been wondering whether we could do something like this by >> treating a table t with columns pk, a1, a2, a3, b1, b2, b3 as two >> tables t1 and t2, one with columns pk, a1, a2, a3 and the other with >> columns pk, b1, b2, b3. SELECT * FROM t would be translated into >> SELECT * FROM t1, t2 WHERE t1.pk = t2.pk. > > Possibly, but you'd be paying tuple overhead twice, which is what I was > looking to avoid with forks. What exactly do you mean by "tuple overhead"? -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
