A database that contains many objects has a larger database
descriptor (DBD).
About this task
If a large number of create, alter, and drop
operations are performed on objects in a database with a large DBD, Db2 might
encounter more contention from the DBD among transactions that access
different objects because storage is not automatically reclaimed in
the DBD.
Procedure
To control the size of DBDs for large databases:
- Monitor and manage DBDs to prevent them from becoming too
large.
Very large DBDs can reduce concurrency and degrade
the performance of SQL operations that create or alter objects because
of increased I/O and logging. DBDs that are created or altered in Db2 Version
6 or later do not need contiguous storage, but can use pieces of approximately
32 KB. Older DBDs require contiguous storage.
- When you create, alter, and drop objects in a database,
use the MODIFY RECOVERY utility to reclaim storage in the DBD.
Storage is not automatically reclaimed in a DBD for these operations.