XML storage object

By default, Db2® database server stores XML documents contained in table columns of type XML in XML storage objects, in much the same way that LOB data is stored apart from the other contents of a table.

XML storage objects are separate from, but dependent upon, their parent table objects. For each XML value stored in a row of an XML table column, Db2 maintains a record called an XML data specifier (XDS), which specifies where to retrieve the XML data stored on disk from the associated XML storage object. When stored in system managed space, the files associated with XML storage objects have the file type extension .xda. An XML storage object is sometimes called an XML data area (XDA).

You can store XML documents of up to 2 gigabytes in size in a database. Because XML data can be quite large, you may want to monitor the buffering activity for XML data separately from the buffering activity for other data. A number of monitor elements are available to help you gauge the buffer pool activity for XML storage objects.

For additional information on space requirements for XML columns that use XML storage objects, see Byte Counts for XML columns without the INLINE LENGTH specified in "CREATE TABLE statement".