Maintenance of secondary indexes and materialized views can cause the latency and bandwidth of concurrent information capture to degrade by orders of magnitude. In order to preserve performance during temporary bursts of update activity, e.g., during load operations, many systems therefore support deferred maintenance, at least for materialized views. However, deferring maintenance means that index or view contents may become out-of-date. In such cases, a seemingly benign choice among alternative query execution plans affects whether query results represent the latest database contents. We propose here a system that distinguishes between the maintenance of of logical contents and physical structure. This distinction lets us compensate for deferred logical maintenance operations while minimizing the impact of deferred physical maintenance operations, and results in support for concurrent high update rates and immediate, index-based query processing with correct transaction semantics.
['Harumi A. Kuno', 'Goetz Graefe']
Deferred maintenance of indexes and of materialized views