1 files changed, 27 insertions, 0 deletions
diff --git a/src/backend/storage/page/bufpage.c b/src/backend/storage/page/bufpage.c
index 6fc5fa4d05b..fdf045a45b0 100644
--- a/src/backend/storage/page/bufpage.c
+++ b/src/backend/storage/page/bufpage.c
@@ -598,6 +598,33 @@ PageGetFreeSpace(Page page)
 }
 
 /*
+ * PageGetFreeSpaceForMultipleTuples
+ *		Returns the size of the free (allocatable) space on a page,
+ *		reduced by the space needed for multiple new line pointers.
+ *
+ * Note: this should usually only be used on index pages.  Use
+ * PageGetHeapFreeSpace on heap pages.
+ */
+Size
+PageGetFreeSpaceForMultipleTuples(Page page, int ntups)
+{
+	int			space;
+
+	/*
+	 * Use signed arithmetic here so that we behave sensibly if pd_lower >
+	 * pd_upper.
+	 */
+	space = (int) ((PageHeader) page)->pd_upper -
+		(int) ((PageHeader) page)->pd_lower;
+
+	if (space < (int) (ntups * sizeof(ItemIdData)))
+		return 0;
+	space -= ntups * sizeof(ItemIdData);
+
+	return (Size) space;
+}
+
+/*
  * PageGetExactFreeSpace
  *		Returns the size of the free (allocatable) space on a page,
  *		without any consideration for adding/removing line pointers.