Conditions and configuration metadata for the ATLAS experiment

In the ATLAS experiment, a system called COMA (Conditions/Configuration Metadata for ATLAS), has been developed to make globally important run-level metadata more readily accessible. It is based on a relational database storing directly extracted, refined, reduced, and derived information from system-specific database sources as well as information from non-database sources. This information facilitates a variety of unique dynamic interfaces and provides information to enhance the functionality of other systems. This presentation will give an overview of the components of the COMA system, enumerate its diverse data sources, and give examples of some of the interfaces it facilitates. We list important principles behind COMA schema and interface design, and how features of these principles create coherence and eliminate redundancy among the components of the overall system. In addition, we elucidate how interface logging data has been used to refine COMA content and improve the value and performance of end-user reports and browsers.