Automatic Workload Driven Index Defragmentation

Queries that scan a B-Tree index can suffer significant I/O performance degradation due to index fragmentation. The task of determining if an index should be defragmented is challenging for DataBase Administrators (DBAs) since today's database engines offer no support for quantifying the impact of defragmenting an index on query I/O performance. Furthermore, DBMSs only support defragmentation at the granularity of an entire B-Tree, which can be very restrictive since defragmentation is an expensive operation and workloads typically access different ranges of an index non-uniformly.

Provided by: VLD Digital Topic: Data Management Date Added: Sep 2011 Format: PDF

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