A common use case when writing API programs and extensions is searching for items with a given attribute value, e.g., get all requirements with a given requirement id. This is traditionally done by creating a filter and calling IswQ. For improved performance, there is a specific call on IswQ to use for the search:
IswItems GetItemsWithAttributeValue(IswItemType itemType, bool includeSubTypes, IswAttributeType attributeType, string attributeValue);
This call should be significantly faster (e.g., up to 80%) and put lower load on the server than using filters.
It can be used for attributes which can be expressed as a string, e.g., string and integer.