A case for fractured mirrors

The Decomposition Storage Model (DSM) vertically partitions all attributes of a given relation. DSM has excellent I/O behavior when the number of attributes touched in the query is small. It also has a better cache footprint than the N-ary storage model (NSM) that is used by most database systems. However, DSM incurs a high cost in reconstructing the original tuple from the partitions. We first revisit some of the performance problems associated with DSM. We suggest a simple indexing strategy and compare different reconstruction algorithms. The paper then proposes a new mirroring scheme, termed fractured mirrors, using both NSM and DSM models. This scheme combines the best aspects of both models, along with the added benefit of mirroring to better serve an ad-hoc query workload. A prototype system has been built using the Shore storage manager and performance is evaluated using queries from the TPCH workload.

• Type: Conference
• Year: 2003
• Where: VLDB
• Authors: Ravishankar Ramamurthy, David J. DeWitt, Qi Su
• Keywords: Ad-hoc Query Workload, Database, DSM Models, N-ary Storage Model, VLDB 2003