| USERID | RECORDLENGTH |
| BUFFER | INCTYPE |
| FILE | RECORD |
| GRANTS | HELP |
| INDEXES | LOG |
| ROWS | CONSISTENT |
| CONSTRAINTS | STATISTICS |
| COMPRESS | FEEDBACK |
| FULL | MLS* |
| OWNER | MLS_LABEL_FORMAT* |
| TABLES | |
| *Trusted Oracle7 Server parameter | |
Default: operating system dependent
The parameter BUFFER determines the maximum number of rows in an array fetched by Export by specifying the size of the buffer. You can calculate the buffer size as follows:
buffer_size = rows_in_array * maximum_row_size
buffer_size is the size in bytes of the buffer into which data rows are fetched. If zero is specified, or if rows contain LONG data, only one row at a time is fetched.
Additional Information: See your Oracle operating system-specific documentation to determine the default value for this parameter.
Specifies how Export/Import will manage the initial extent for table data.
The default, COMPRESS=Y, causes Export to flag the table data for consolidation into one initial extent upon Import.
If COMPRESS=N is specified, Export will sum the lengths of all current extents on export and Import will use that value as the size of the initial extent for the imported table data. Note that, when a table has had many deletes, this size may be much larger than the table actually requires.
Note: Although used extents are consolidated into one extent upon import, you must request consolidation when exporting, because your request causes the table definition to be exported differently. Thus, if you request consolidation when exporting, you can import the data in consolidated form only.
Specifies whether Export will use the SET TRANSACTION READ ONLY statement to insure that the export is consistent to a single point in time. Specifying CONSISTENT=Y is important when other applications will be updating the database after an export has started because these transactions will be rolled back, if necessary.
If you specify CONSISTENT=Y, a rollback segment must be retained for the duration of the export to allow backing out of the effects of any uncommitted transactions when a table is exported. Note that, if the volume of updates is large, the rollback segment will itself be large. In addition, the export of each table will be slower, since the rollback segment must be scanned for uncommitted transactions.
Note: CONSISTENT cannot be used with an incremental export.
Suggestion: To minimize the time and space required for such exports, tables that need to remain consistent should be exported separately from those that do not.
For example, export the EMP and DEPT tables together in a consistent export, then export the remainder of the database in a second pass.
Exporting the minimum number of objects that must be guaranteed consistent helps to reduce the chances of encountering a "snapshot too old" error.
This error occurs when rollback space has been used up, and space taken up by committed transactions is reused for new transactions. Reusing space in the rollback segment allows database integrity to be preserved with minimum space requirements, but it imposes a limit on the amount of time that a read-consistent image can be preserved.
If a committed transaction has been overwritten and the information is needed for a read-consistent view of the database, then a "snapshot too old" error results.
To avoid this error, minimize the time taken by a read-consistent export (by restricting the number of objects exported and, if possible, by reducing the database transaction rate). Also, make the rollback segment as large as possible.
A flag to indicate whether to export table constraints.
Specifying DIRECT=Y causes export to extract data by reading the data directly, bypassing the SQL Command Processing layer (evaluating buffer). This method can be much faster than a conventional path export.
Performance can also be improved by using direct path export with the database in direct read mode. Contention for resources with other users is eliminated because database blocks are read into the private buffer cache, rather than a public buffer cache.
For more information about direct path exports, see ![[*]](jump.gif)
.
Default: 0 (zero)
Specifies that Export should display a progress meter in the form of a dot for x number of rows exported. For example, were you to specify FEEDBACK=10, Export would display a dot each time 10 rows had been exported. The FEEDBACK value applies to all tables being exported, it cannot be set on a per table basis.
Default: EXPDAT.DMP
The name of the export file. The default extension is .DMP, but you can specify any extension.
Specifies whether Export should export the entire database or not. Specify FULL=Y to export in full database mode (you must have the EXP_FULL_DATABASE role enabled to do this).
Specifies whether grants should be exported or not.
Displays a help message with descriptions of the Export parameters.
Specifies the type of incremental export. Options are COMPLETE, CUMULATIVE, and INCREMENTAL. See the section in this chapter called "Incremental, Cumulative and Complete Exports" for a description of these options.
Specifies whether indexes should be exported or not.
Specifies a file name to receive informational and error messages. For example:
EXP system/manager LOG=export.log
If this parameter is specified, messages are logged in the log file and displayed via the terminal display.
The Export utility can be used on any Trusted Oracle7 database to produce a normal export file. In DBMS Mandatory Access Control (MAC) mode, the MLS parameter can also be specified. With this parameter, the Multi-Level Security (MLS) labels on each row and object in the database are included in the export file. This parameter is further described in the Trusted Oracle7 Server Administrator's Guide.
MLS_LABEL_ FORMAT
This parameter allows you to override the default format specified in the database for human-readable MLS labels. The format you specify will be used in the export file instead of the format defined by the database initialization parameter. This parameter is further described in the Trusted Oracle7 Server Administrator's Guide.
Specifies a list of usernames whose objects will be exported. Specify OWNER=userlist to export in user mode.
A flag to indicate whether to record an incremental or cumulative export in database tables SYS.INCVID, SYS.INCFIL, and SYS.INCEXP. See .
Default: operating system dependent
Specifies the length, in bytes, of the file record. The RECORDLENGTH parameter is necessary when you must transfer the export file to another operating system that uses a different default value.
Additional Information: See your Oracle operating system-specific documentation for the system being exported to determine the proper value, or when you want to create a file with a different record size.
Specifies whether the rows of table data should be exported or not.
Specifies the type of database optimizer statistics to generate when the exported data is imported later. Options are ESTIMATE, COMPUTE, and NONE. See Chapter 13 of the Oracle7 Server Concepts manual for information about the optimizer.
Specifies list of table names to export. Specify TABLES=tablelist to export in table mode.
Specifies the username/password of the user initiating the export.
EXP system/manager OWNER=jones TABLES=scott.emp
Similarly, OWNER conflicts with FULL=Y.
Although ROWS=N and INCTYPE=INCREMENTAL can both be used, specifying ROWS=N (no data) defeats the purpose of incremental exports, which is to make a backup copy of tables that have changed.