CERN Accelerating science

ATLAS Slides
Report number	ATL-SOFT-SLIDE-2023-033
Title	HBase / Phoenix-based Data Collection and Storage for the ATLAS EventIndex
Author(s)	Garcia Montoro, Carlos (Univ. of Valencia and CSIC (ES)) ; Sanchez Martinez, Francisco Javier (Univ. of Valencia and CSIC (ES)) ; Barberis, Dario (INFN e Universita Genova (IT)) ; Gonzalez De La Hoz, Santiago (Univ. of Valencia and CSIC (ES)) ; Salt, Jose (Univ. of Valencia and CSIC (ES))
Corporate author(s)	The ATLAS collaboration
Collaboration	ATLAS Collaboration
Submitted to	26th International Conference on Computing in High Energy & Nuclear Physics, Norfolk, Virginia, Us, 8 - 12 May 2023
Submitted by	carlos.garcia.montoro@cern.ch on 26 Mar 2023
Subject category	Particle Physics - Experiment
Accelerator/Facility, Experiment	CERN LHC ; ATLAS
Free keywords	ATLAS ; EventIndex ; Hadoop ; HBase ; Phoenix
Abstract	The ATLAS EventIndex is the global catalogue of all ATLAS real and simulated events. During the LHC long shutdown between Run 2 (2015-2018) and Run 3 (2022-2025) its components were substantially revised, and a new system has been deployed for the start of Run 3 in Spring 2022. The new core storage system is based on HBase tables with a Phoenix interface. It allows faster data ingestion rates and scales better than the old system. This paper describes the data collection, the technical design of the core storage, and the properties that make it performant: The compact and optimized design of the events table, which already holds more than 400 billion entries, and all the auxiliary tables; The EventIndex Supervisor, in charge of orchestrating the whole data collection, has been simplified thanks to the loaders, the Spark jobs that load the data into the new core system. The extractors, in charge of preparing the pieces of data that the loaders will put into the final back-end, have been updated too. The data migration from HDFS to HBase and Phoenix is also described.