Large XML Schema Collections and Out-of-Memory Conditions
Topic Status: Some information in this topic is preview and subject to change in future releases. Preview information describes new features or changes to existing features in Microsoft SQL Server 2016 Community Technology Preview 2 (CTP2).
During a call to the built-in XML_SCHEMA_NAMESPACE() function on a large XML schema collection, or when you try to drop large XML schema collections, an out-of-memory condition may occur. The following are solutions you can use to handle this:
When the system load is light, use the DROP_XML_SCHEMA_COLLECTION command. If this fails, put the database in single-user mode by using the ALTER DATABASE statement and trying DROP XML SCHEMA COLLECTION again. If the XML schema collection exists in master, model, or tempdb, a server restart is required for single-user mode.
When you call the XML_SCHEMA_NAMESPACE, you can try to retrieve a single XML schema namespace, you can try the call when the system load is lighter, or you can try the call in single-user mode.