Evolution of the ATLAS CREST conditions DB project

The CREST project is a new realization of the conditions DB with the REST API and JSON support for the ATLAS experiment. This project allows to simplify the conditions data structure and to optimize the data access. The CREST development requires not only the client C++ library (CrestApi) but also the various tools for testing software and validating data. A command line client realizes a quick access to the stored data. A set of the utilities was used to make a dump of the data from CREST to the file system and to test the client library and the CREST server using the dummy data. Now CREST software is being tested using the real conditions data converted with the COOL to CREST converter. The Athena code (ATLAS event processing software framework) was modified to operate with the new conditions data source.