  Because the presence of views enhances query performance, materialized views
are increasingly being supported by commercial database/data warehouse systems.
Whenever the data warehouse is updated, the materialized views must also be
updated. However, whereas the amount of data entering a warehouse, the query
loads, and the need to obtain up-to-date responses are all increasing, the time
window available for making the warehouse up-to-date is shrinking. These trends
necessitate efficient techniques for the maintenance of materialized views.
  In this paper, we show how to find an efficient plan for maintenance of a
{\em set} of views, by exploiting common subexpressions between different view
maintenance expressions. These common subexpressions may be materialized
temporarily during view maintenance. Our algorithms also choose
subexpressions/indices to be materialized permanently (and maintained along
with other materialized views), to speed up view maintenance. While there has
been much work on view maintenance in the past, our novel contributions lie in
exploiting a recently developed framework for multiquery optimization to
efficiently find good view maintenance plans as above. In addition to faster
view maintenance, our algorithms can also be used to efficiently select
materialized views to speed up workloads containing queries.
