Add comments about STORAGE option for GIN

diff --git a/doc/src/sgml/xindex.sgml b/doc/src/sgml/xindex.sgml
index 176958d9ee36428da9b564680c56f94d53728188..3a5a7cb78c9bcdb52db4eb525d602f8057eb44d3 100644 (file)
--- a/doc/src/sgml/xindex.sgml
+++ b/doc/src/sgml/xindex.sgml
@@ -1,4 +1,4 @@
-
+
 
 
  Interfacing Extensions To Indexes
@@ -822,11 +822,12 @@ CREATE OPERATOR CLASS polygon_ops
         STORAGE box;
 
 
-   At present, only the GiST index method supports a
+   At present, only the GiST and GIN index method supports a
    STORAGE type that's different from the column data type.
    The GiST compress and decompress support
    routines must deal with data-type conversion when STORAGE
-   is used.
+   is used. Functions named extractValue and extractQuery
+   do conversation into internally used types for GIN.