diff --git a/contrib/pageinspect/rawpage.c b/contrib/pageinspect/rawpage.c
index 9043fa37bd9..d91bcfc1b1c 100644
--- a/contrib/pageinspect/rawpage.c
+++ b/contrib/pageinspect/rawpage.c
@@ -24,6 +24,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "storage/bufmgr.h"
+#include "storage/smgr.h"
 #include "utils/builtins.h"
 
 PG_MODULE_MAGIC;
@@ -130,9 +131,13 @@ get_raw_page_internal(text *relname, ForkNumber forknum, BlockNumber blkno)
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("cannot access temporary tables of other sessions")));
 
-	if (blkno >= RelationGetNumberOfBlocks(rel))
-		elog(ERROR, "block number %u is out of range for relation \"%s\"",
-			 blkno, RelationGetRelationName(rel));
+	RelationOpenSmgr(rel);
+
+	if (blkno >= smgrnblocks(rel->rd_smgr, forknum))
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("block number %u is out of range for relation \"%s\"",
+						blkno, RelationGetRelationName(rel))));
 
 	/* Initialize buffer to copy to */
 	raw_page = (bytea *) palloc(BLCKSZ + VARHDRSZ);