*** a/src/backend/access/transam/xloginsert.c
--- b/src/backend/access/transam/xloginsert.c
***************
*** 667,676 **** XLogRecordAssemble(RmgrId rmid, uint8 info,
  		{
  			samerel = true;
  			bkpb.fork_flags |= BKPBLOCK_SAME_REL;
- 			prev_regbuf = regbuf;
  		}
  		else
  			samerel = false;
  
  		/* Ok, copy the header to the scratch buffer */
  		memcpy(scratch, &bkpb, SizeOfXLogRecordBlockHeader);
--- 667,676 ----
  		{
  			samerel = true;
  			bkpb.fork_flags |= BKPBLOCK_SAME_REL;
  		}
  		else
  			samerel = false;
+ 		prev_regbuf = regbuf;
  
  		/* Ok, copy the header to the scratch buffer */
  		memcpy(scratch, &bkpb, SizeOfXLogRecordBlockHeader);