Automated Statistics Collection in DB2 UDB

The use of inaccurate or outdated database statistics by the query optimizer in a relational DBMS often results in a poor choice of query execution plans and hence unacceptably long query processing times. Configuration and maintenance of these statistics has traditionally been a time-consuming manual operation, requiring that the database administrator (DBA) continually monitor query performance and data changes in order to determine when to refresh the statistics values and when and how to adjust the set of statistics that the DBMS maintains. In this paper we describe the new Automated Statistics Collection (ASC) component of IBM® DB2® Universal Database™ (DB2 UDB). This autonomic technology frees the DBA from the tedious task of manually supervising the collection and maintenance of database statistics. ASC monitors both the update-delete-insert (UDI) activities on the data as well as query feedback (QF), i.e., the results of the queries that are executed on the data. ASC uses ...

• Type: Conference
• Year: 2004
• Where: VLDB
• Authors: Ashraf Aboulnaga, Peter J. Haas, Sam Lightstone, Guy M. Lohman, Volker Markl, Ivan Popivanov, Vijayshankar Raman
• Keywords: Database, Database Statistics, Query Execution Plans, Statistics, VLDB 2004