Property:Query duration
From Linux Web Expert
"Query duration" is a predefined property containing a time value (in seconds) that was required to complete the query execution and is provided by Semantic MediaWiki. This property is pre-deployed (also known as special property) and comes with additional administrative privileges but can be used just like any other user-defined property.
This is the page of special property Query duration. It lists all pages using this special property. See the help page Special property Query duration for further information.