diff --git a/src/include/access/hash.h b/src/include/access/hash.h
index 543d802..c3fc117 100644
--- a/src/include/access/hash.h
+++ b/src/include/access/hash.h
@@ -230,9 +230,15 @@ typedef HashScanOpaqueData *HashScanOpaque;
  *
  * There is no particular upper limit on the size of mapp[], other than
  * needing to fit into the metapage.  (With 8K block size, 1024 bitmaps
- * limit us to 256 GB of overflow space...)
+ * limit us to 256 GB of overflow space...).  For smaller block size we
+ * can not use 1024 bitmaps otherwise the mapp[] will cross the
+ * block size. However, it is better to use the BLCKSZ to determine the
+ * maximum number of bitmaps. For example with current formula, if BLCKSZ
+ * is 1K then there will be 128 bitmaps. This will make mapp[] size to
+ * 512 bytes, now including the space for page opaque and meta data
+ * header, the total size will be 968 bytes.
  */
-#define HASH_MAX_BITMAPS			1024
+#define HASH_MAX_BITMAPS			Max(BLCKSZ / 8, 1024)
 
 #define HASH_SPLITPOINT_PHASE_BITS	2
 #define HASH_SPLITPOINT_PHASES_PER_GRP	(1 << HASH_SPLITPOINT_PHASE_BITS)