Re: tablespace patch

"Christopher Kings-Lynne" <chriskl@familyhealth.com.au> writes:
> First thing tho, apparently, is to refactor smgr and bufmgr to use
> only file descriptors am I right?

Well, they shouldn't be using Relations, for sure.  Something based
on knowing only RelFileNode would be appropriate.  Vadim wrote a few
messages about this back when he was still active --- check the
archives.

In my mind a touchstone for a proper redesign of this layer is that
the checkpoint process should not be handicapped by not being a full
backend.  Right now, all checkpoint buffer writes happen via
smgrblindwrt, which is a nontrivial performance loss.  Ideally the
notion of "blind write" should go away, because you shouldn't need
anything more than the RelFileNode and block number, which are both
available from the shared buffer descriptor.

Tablespaces per se will likely require adding an additional field to
RelFileNode, but that's a separate consideration.
        regards, tom lane