Add views to SQL support

docs/src/main/sphinx/connector/iceberg.rst

@@ -91,7 +91,8 @@ supports the following features:
 * :doc:`/sql/insert`
 * :doc:`/sql/delete`, see also :ref:`iceberg-delete`
 * :ref:`sql-schema-table-management`, see also :ref:`iceberg-tables`
-* :ref:`sql-materialized-views-management`
+* :ref:`sql-materialized-views-management`, see also
+  :ref:`iceberg-materialized-views`
 * :ref:`sql-views-management`
 
 .. _iceberg-tables:
@@ -197,6 +198,8 @@ The connector supports queries of the table partitions.  Given a table ``custome
 ``SELECT * FROM iceberg.testdb."customer_orders$partitions"`` shows the table partitions, including the minimum
 and maximum values for the partition columns.
 
+.. _iceberg-table-properties:
+
 Iceberg table properties
 ------------------------
 
@@ -226,3 +229,35 @@ and a file system location of ``/var/my_tables/test_table``::
         format = 'PARQUET',
         partitioning = ARRAY['c1', 'c2'],
         location = '/var/my_tables/test_table')
+
+.. _iceberg-materialized-views:
+
+Materialized views
+------------------
+
+The Iceberg connector supports :ref:`sql-materialized-views-management`. In the
+underlying system each materialized view consists of a view definition and an
+Iceberg storage table. The storage table name is stored as a materialized view
+property. The data is stored in that storage table.
+
+You can use the :ref:`iceberg-table-properties` to control the created storage
+table and therefore the layout and performance. For example, you can use the
+following clause with :doc:`/sql/create-materialized-view` to use the ORC format
+for the data files and partition the storage per day using the column
+``_date``::
+
+    WITH ( format = 'ORC', partitioning = ARRAY['event_date'] )
+
+Updating the data in the materialized view with
+:doc:`/sql/refresh-materialized-view` deletes the data from the storage table,
+and inserts new data that is the result of executing the materialized view
+query.
+
+.. warning::
+
+    There is a small time window between the commit of the delete and insert,
+    when the materialized view is empty. If the commit operation for the insert
+    fails, the materialized view remains empty.
+
+Dropping a materialized view with :doc:`/sql/refresh-materialized-view` removes
+the definition and the storage table.