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Oracle Tips by Burleson |
Alteration of Clusters
Only the sizing and storage parameters of
clusters may be altered, via the ALTER CLUSTER command. No
additional columns may be added to, or removed from, the cluster
using the ALTER CLUSTER command. The format of the command follows:
See Code Depot
The definitions for the parameters in this
code are the same as for the CREATE TABLE, CREATE CLUSTER, and
storage clause definitions.
In Oracle, the structure of a cluster and
its associated index and tables can be analyzed for consistency and
for sizing data using the ANALYZE CLUSTER command. The format of
this command follows:
See Code Depot
where:
COMPUTE STATISTICS. Calculates statistics
based on all rows.
ESTIMATE STATISTICS. Calculates an estimate
of the statistics based on n ROWS or PERCENT of rows in table.
VALIDATE STRUCTURE. Validates that the table
and its indexes are consistent and not corrupted.
CASCADE. For clusters, validates all tables
in cluster.
DELETE STATISTICS. Removes current
statistics.
The results appear in the
DBA_CLUSTERS view.
To verify a cluster’s integrity, use
the following version of the ANALYZE command.
ANALYZE CLUSTER [schema.]cluster
VALIDATE STRUCTURE [CASCADE]
The CASCADE option forces analysis of all
indexes and tables in the cluster.
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