Add new vpl_num_allocated_pages member to VPageListData.

It will keep track the number of pages allocated so that
vacuum could allocate twice of the previous allocation.
This will greatly reduce the total memory consumption of
vacuum.

src/include/commands/vacuum.h

@@ -6,7 +6,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: vacuum.h,v 1.20 1999/05/25 22:42:43 momjian Exp $
+ * $Id: vacuum.h,v 1.20.2.1 1999/08/25 11:32:52 ishii Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -46,6 +46,7 @@ typedef struct VPageListData
 {
 	int			vpl_empty_end_pages;	/* Number of "empty" end-pages */
 	int			vpl_num_pages;	/* Number of pages in vpl_pagedesc */
+	int			vpl_num_allocated_pages;	/* Number of allocated pages in vpl_pagedesc */
 	VPageDescr *vpl_pagedesc;	/* Descriptions of pages */
 } VPageListData;