On Tue, May 31, 2005 at 02:55:29PM -0600, Jonah H. Harris wrote: > Hey everyone, > > I'm sure this has been thought of but was wondering whether anyone had > discussed the allowance of run-time block size specifications at the > tablespace level? I know that a change such as this would substantially > impact buffer operations, transactions, access methods, the storage > manager, and a lot of other stuff, however it would give an > administrator the ability to inhance performance for specific applications.
The problem I see with this proposal is that the buffer manager knows how to handle only a equally-sized pages. And the shared memory stuff gets sized according to size * num_pages. So what happens if a certain tablespace A with pagesize=X gets to have a lot of its pages cached, evicting pages from tablespace B with pagesize=Y, where Y < X? While I think it could be workable to make the buffer manager handle variable-sized pages, it could prove difficult to handle the shared memory. (We can't resize it while the server is running.) -- Alvaro Herrera (<alvherre[a]surnet.cl>) "La principal característica humana es la tontería" (Augusto Monterroso) ---------------------------(end of broadcast)--------------------------- TIP 8: explain analyze is your friend
