Purpose 
Procedures 
Description 
Gather statistics 
GATHER_INDEX_STATS
GATHER_TABLE_STATS
GATHER_SCHEMA_STATS
GATHER_DATABASE_STATS
GENERATE_STATS

The GATHER_STATS packages collect statistics from tables and indexes. The GENERATE_STATS procedure generates the statistics for an object from a group of related objects. 
Delete statistics 
DELETE_COLUMN_STATISTICS
DELETE_TABLE_STATISTICS
DELETE_INDEX_STATISTICS
DELETE_SCHEMA_STATISTICS
DELETE_DATABASE_STATISTICS

Removes any existing statistics from the data dictionary or an external table, if specified. 
Use external table to store statistics 
CREATE_STAT_TABLE
DROP_STAT_TABLE 
Creates and drops an external table to store statistics. 
Export statistics 
EXPORT_COLUMN_STATISTICS
EXPORT_TABLE_STATISTICS
EXPORT_INDEX_STATISTICS
EXPORT_SCHEMA_STATISTICS
EXPORT_DATABASE_STATISTICS

Exports statistics to an external table from the data dictionary. 
Import statistics 
IMPORT_COLUMN_STATISTICS
IMPORT_TABLE_STATISTICS
IMPORT_INDEX_STATISTICS
IMPORT_SCHEMA_STATISTICS
IMPORT_DATABASE_STATISTICS

Imports statistics from an external table to the data dictionary. 
Convert values 
CONVERT_RAW_VALUE
PREPARE_COLUMN_VALUES

Converts values to (PREPARE_COLUMN_VALUE ) and from (CONVERT_RAW_VALU E), the Oracle internal format for statistics. 
Set statistics 
SET_COLUMN_STATS
SET_INDEX_STATS SET_TABLE_STATS 
You can use these procedures to set values for statistics. Use only when you have a complete understanding of how statistics are used by the optimizer. 
Get statistics 
GET_COLUMN_STATS GET_INDEX_STATS GET_TABLE_STATS 
Used to retrieve values from statistics tables. 