Foundations and Trends R � in Databases Vol. 1, No. 2 (2007) 141–259 c � 2007 J. M. Hellerstein, M. Stonebraker and J. Hamilton DOI: 10.1561/1900000002 Architecture of a Database System Joseph M. Hellerstein1 , Michael Stonebraker2 and James Hamilton3 1 University of California, Berkeley, USA, hellerstein@cs.berkeley.edu 2 Massachusetts Institute of Technology, USA 3 Microsoft Research, USA Abstra