diff --git a/doc/src/sgml/intarray.sgml b/doc/src/sgml/intarray.sgml
index 956c01d749..fdeedc6409 100644
--- a/doc/src/sgml/intarray.sgml
+++ b/doc/src/sgml/intarray.sgml
@@ -453,7 +453,7 @@
 CREATE TABLE message (mid INT PRIMARY KEY, sections INT[], ...);
 
 -- create specialized index with signature length of 32 bytes
-CREATE INDEX message_rdtree_idx ON message USING GIST (sections gist__int_ops(siglen=32));
+CREATE INDEX message_rdtree_idx ON message USING GIST (sections gist__intbig_ops (siglen = 32));
 
 -- select messages in section 1 OR 2 - OVERLAP operator
 SELECT message.mid FROM message WHERE message.sections && '{1,2}';