Re: Tablespaces

I'm starting to review this patch, and almost immediately came across
what seemed a spectacularly bad idea:

*** src/backend/storage/buffer/bufmgr.c 8 May 2004 19:09:25 -0000 1.165
--- src/backend/storage/buffer/bufmgr.c 26 May 2004 06:21:01 -0000
***************
*** 1148,1152 ****
{
bufHdr = &LocalBufferDescriptors[i];
! if (RelFileNodeEquals(bufHdr->tag.rnode, rnode))
{
bufHdr->flags &= ~(BM_DIRTY | BM_JUST_DIRTIED);
--- 1148,1156 ----
{
bufHdr = &LocalBufferDescriptors[i];
! /* special case for default tblNode */
! if (RelFileNodeEquals(bufHdr->tag.rnode, rnode) ||
! (!OidIsValid(rnode.tblNode) &&
! bufHdr->tag.rnode.relNode == rnode.relNode &&
! bufHdr->tag.rnode.dbNode == rnode.dbNode))
{
bufHdr->flags &= ~(BM_DIRTY | BM_JUST_DIRTIED);

There has got to be a better way than this. In the first place the
code seems able to seize on the wrong buffer if it's not checking
all three fields; in the second place, if the weak matching is correct
here why is it not needed everyplace else?

What's the purpose of this?

regards, tom lane