diff --git a/contrib/pgstattuple/pgstatindex.c b/contrib/pgstattuple/pgstatindex.c
index ceabd862a86..0aa517a870a 100644
--- a/contrib/pgstattuple/pgstatindex.c
+++ b/contrib/pgstattuple/pgstatindex.c
@@ -66,7 +66,6 @@ typedef struct BTIndexStat
 	uint32		level;
 	BlockNumber root_blkno;
 
-	uint64		root_pages;
 	uint64		internal_pages;
 	uint64		leaf_pages;
 	uint64		empty_pages;
@@ -133,7 +132,6 @@ pgstatindex(PG_FUNCTION_ARGS)
 	}
 
 	/* -- init counters -- */
-	indexStat.root_pages = 0;
 	indexStat.internal_pages = 0;
 	indexStat.leaf_pages = 0;
 	indexStat.empty_pages = 0;
@@ -166,7 +164,11 @@ pgstatindex(PG_FUNCTION_ARGS)
 
 		/* Determine page type, and update totals */
 
-		if (P_ISLEAF(opaque))
+		if (P_ISDELETED(opaque))
+			indexStat.deleted_pages++;
+		else if (P_IGNORE(opaque))
+			indexStat.empty_pages++;	/* this is the "half dead" state */
+		else if (P_ISLEAF(opaque))
 		{
 			int			max_avail;
 
@@ -183,12 +185,6 @@ pgstatindex(PG_FUNCTION_ARGS)
 			if (opaque->btpo_next != P_NONE && opaque->btpo_next < blkno)
 				indexStat.fragments++;
 		}
-		else if (P_ISDELETED(opaque))
-			indexStat.deleted_pages++;
-		else if (P_IGNORE(opaque))
-			indexStat.empty_pages++;
-		else if (P_ISROOT(opaque))
-			indexStat.root_pages++;
 		else
 			indexStat.internal_pages++;
 
@@ -220,7 +216,7 @@ pgstatindex(PG_FUNCTION_ARGS)
 		snprintf(values[j++], 32, "%d", indexStat.level);
 		values[j] = palloc(32);
 		snprintf(values[j++], 32, INT64_FORMAT,
-				 (indexStat.root_pages +
+				 (1 +		/* include the metapage in index_size */
 				  indexStat.leaf_pages +
 				  indexStat.internal_pages +
 				  indexStat.deleted_pages +
diff --git a/doc/src/sgml/pgstattuple.sgml b/doc/src/sgml/pgstattuple.sgml
index a55b35cb3f1..7f1ae8d3048 100644
--- a/doc/src/sgml/pgstattuple.sgml
+++ b/doc/src/sgml/pgstattuple.sgml
@@ -146,13 +146,13 @@ test=> SELECT * FROM pgstatindex('pg_cast_oid_index');
 -[ RECORD 1 ]------+------
 version            | 2
 tree_level         | 0
-index_size         | 8192
+index_size         | 16384
 root_block_no      | 1
 internal_pages     | 0
 leaf_pages         | 1
 empty_pages        | 0
 deleted_pages      | 0
-avg_leaf_density   | 50.27
+avg_leaf_density   | 54.27
 leaf_fragmentation | 0
 </programlisting>
      </para>
@@ -186,13 +186,13 @@ leaf_fragmentation | 0
        <row>
         <entry><structfield>index_size</structfield></entry>
         <entry><type>bigint</type></entry>
-        <entry>Total number of pages in index</entry>
+        <entry>Total index size in bytes</entry>
        </row>
 
        <row>
         <entry><structfield>root_block_no</structfield></entry>
         <entry><type>bigint</type></entry>
-        <entry>Location of root block</entry>
+        <entry>Location of root page (zero if none)</entry>
        </row>
 
        <row>
@@ -236,6 +236,13 @@ leaf_fragmentation | 0
     </informaltable>
     </para>
 
+    <para>
+     The reported <literal>index_size</> will normally correspond to one more
+     page than is accounted for by <literal>internal_pages + leaf_pages +
+     empty_pages + deleted_pages</literal>, because it also includes the
+     index's metapage.
+    </para>
+
     <para>
      As with <function>pgstattuple</>, the results are accumulated
      page-by-page, and should not be expected to represent an