Sometimes the creation of a custom “uxy” property column fails.
However, creation is usually tried again automatically and the “uxy” property column from the previous creation attempt is deleted from the database. In rare cases though, the “uxy” property column from the previous creation attempt is not deleted from the database. When this situation occurs, two columns for the same property exist in the database. One column is used and the other column is unused.
Performance is unaffected if you accidentally create an index on the wrong custom property column. Therefore, when you plan to index a custom property column, consider running the following query against the ColumnDefinition table to ensure that you have selected the correct custom property column:
SELECT dbg_table_name, column_name from ColumnDefinition WHERE lower(column_name) like lower('%_propertyname')
You can also display the columns in a table by running this query:
SELECT dbg_table_name, column_name from ColumnDefinition WHERE lower(column_name) like lower('%_propertyname')
For more information, see Custom properties and the “uxy” prefix.