OMS Data Aggregation and Management in the CMS Experiment

The Online Monitoring System (OMS) at the Compact Muon Solenoid (CMS) experiment at CERN collects and combines various non-event data sources, allowing users to view, compare, and correlate real-time and historical information. The OMS data warehouse (DWH) constitutes the foundation of the Online Monitoring System (OMS) architecture within CMS, responsible for the storage and manipulation of non-event data within ORACLE databases. Using PL/SQL code, the DWH orchestrates the data aggregation and processing from several sources, inheriting and revamping code from a previous project known as Web Based Monitoring (WBM) to meet evolving requirements. The main goals of the WBM databases restructuring were: the modernization of inherited PL/SQL code, necessitating the creation of new aggregation tables and the implementation of enhancements such as standardized naming conventions, improved development workflows, and continuous integration strategies. DWH is composed of multiple Oracle schemas and integrates external PL/SQL libraries, particularly the CERN Beams Common4Oracle library, which consolidates common functionalities from various CERN Beams department databases into a unified codebase for widespread application. This article describes into the architecture and development strategies employed within the OMS data warehouse, underscoring its role in facilitating efficient data aggregation and management within the OMS project in the CMS experiment at CERN.