Generating Statistics on Imported Data

STATISTICS=COMPUTE

STATISTICS=ESTIMATE

When one of these options is specified during the export, all database objects that have had ANALYZE applied to them are exported with the commands necessary to generate the appropriate statistics (estimated or computed) on import.

Note: Generation of statistics is limited to those objects that already had them before export. So statistics are not suddenly generated on every object in the database.

If your installation generally uses either estimated or computed statistics, then it is a good idea to include one of these commands whenever you use Export. The cost during export is negligible -- statistics are not recorded in the export file, only a command to generate them. See Chapter 13 of the Oracle7 Server Concepts manual for more information about the optimizer.

By issuing this command during export, you ensure that the appropriate statistics are gathered when the data is imported. If your export file was created without this command, or if you have changed your method of collecting statistics, use Import's INDEXFILE option to generate a list of imported objects. Then edit that list to produce a series of ANALYZE commands on them. (For more information, see the INDEXFILE parameter ).