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