Profiling query data (or more precise Query meta data) was initially introduced as part of Semantic MediaWiki 1.8.0 in an effort to allow to track individual queries. The query data container is specified as a subobject stored with special property "Has query" that represents meta information about
The following information are collected as part of the profiler subobject:
- Query size (since Semantic MediaWiki 1.8.0)
- Query depth (since Semantic MediaWiki 1.8.0)
- Query format (since Semantic MediaWiki 1.8.0)
- Query string (since Semantic MediaWiki 1.8.0)
- Query duration (since Semantic MediaWiki 1.9.02 - disabled by default)
- Query parameters (since Semantic MediaWiki 2.5.03 - disabled by default)
The "Has query" subobject is generated from an individual query and identifiable by an internal ID such as "_QUERY352c85af2335a1ef9cff0345bd12f0fd".
If the content of a query changes so does its internal ID but if two queries share the same parameters (means that the queries are equal) then only one query profile is maintained (both queries will inherit the same query ID) for that particular query.
In case "Query duration" and "Query parameters" are enabled (both disabled by default), durations and parameters are stored for each individual query including those with only one profile.