Keyword Type Groups were created for high volume processing and efficient document retrieval. They provide many significant performance advantages. With Keyword Type Groups, all or most keywords for a Document Type are stored in one database table. As a result, the number of queries required to read and write Keyword Values for a document are reduced to one database transaction. Keyword Type Groups can greatly reduce the demand on the database, particularly for Document Types with a large number of Keyword Types (especially where Workflow is used).
Additionally, Keyword Type Groups can allow for the creation of custom indexes that better support the types of searches that specific users are performing. They provide little to no performance benefit if users are searching by a single Keyword Type. When searching by multiple Keyword Types, they can reduce activity by potentially large amounts. It is considered a best practice to create Keyword Type Groups whenever multiple Keyword Types are repeatedly used for retrieving documents.