Database Reference
In-Depth Information
By default, the dbms_stats package modifies the data dictionary directly. Nevertheless, with many of its
procedures and functions, it's also possible to work on a user-defined table stored outside the data dictionary.
This is what I call the backup table .
Because managing statistics means much more than simply gathering them, the dbms_stats package provides
the following key features (see Figure 8-1 ):
Gathering object statistics and, optionally, storing the current statistics in a backup table
before overwriting them
Locking and unlocking object statistics stored in the data dictionary
Copying object statistics from one partition or subpartition to another
Restoring object statistics in the data dictionary
Deleting object statistics stored in the data dictionary or a backup table
Exporting object statistics from the data dictionary to a backup table
Importing object statistics from a backup table to the data dictionary
Getting (extracting) object statistics stored in the data dictionary or a backup table
Setting (modifying) object statistics stored in the data dictionary or a backup table
Figure 8-1. The dbms_stats package provides a comprehensive set of features to manage object statistics
Note that moving statistics between databases is performed by means of a generic data movement utility (for
example, Data Pump), not with the dbms_stats package itself.
Depending on the granularity and the operation you want to execute, Table 8-1 shows that the dbms_stats
package provides different procedures and functions. For example, if you want to operate on a single schema, the
dbms_stats package provides gather_schema_stats , delete_schema_stats , lock_schema_stats , unlock_schema_stats ,
restore_schema_stats , export_schema_stats , and import_schema_stats .
 
Search WWH ::




Custom Search