GIN stuck in loop during PITR

[Andreas Seltenreich <andreas+pg(at)gate450(dot)dyndns(dot)org>]

I'm just experimenting a bit with GIN, and it is occasionally getting
stuck looping in findParents() during WAL replay.

The attached patch seems to fix it. I also had to set ptr->off as
advertised in the comment above the function to avoid triggering
assertions.

GIN isn't fully transparent to me yet, so it is quite likely that I am
missing something...

regards,
andreas

Index: ginbtree.c
===================================================================
RCS file: /projects/cvsroot/pgsql/src/backend/access/gin/ginbtree.c,v
retrieving revision 1.1
diff -c -r1.1 ginbtree.c
*** ginbtree.c	2 May 2006 11:28:54 -0000	1.1
--- ginbtree.c	25 May 2006 18:12:13 -0000
***************
*** 202,208 ****
  	for(;;) {
  		buffer = ReadBuffer(btree->index, blkno);
  		LockBuffer(buffer, GIN_EXCLUSIVE);
! 		page = BufferGetPage(root->buffer);
  		if ( GinPageIsLeaf(page) )
  			elog(ERROR, "Lost path");
  
--- 202,208 ----
  	for(;;) {
  		buffer = ReadBuffer(btree->index, blkno);
  		LockBuffer(buffer, GIN_EXCLUSIVE);
! 		page = BufferGetPage(buffer);
  		if ( GinPageIsLeaf(page) )
  			elog(ERROR, "Lost path");
  
***************
*** 224,229 ****
--- 224,230 ----
  			ptr->blkno = blkno;
  			ptr->buffer = buffer;
  			ptr->parent = root; /* it's may be wrong, but in next call we will correct */
+ 			ptr->off = offset;
  			stack->parent = ptr;
  			return;
  		}