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The main content of this article is to explain "exp error and why exp can not derive some table structure reasons", interested friends may wish to take a look. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn "exp error report and why exp can't derive some table structure."

There is a new feature in 11G, when the table has no data, segment is not allocated to save space.

Solution:

Set deferred_segment_creation parameters

Modify configuration parameters

Sqlplus / nolog

SQL > connect system/password as sysdba

SQL > show parameter deferred_segment_creation

You will see that it defaults to true, modify.

SQL > alter system set deferred_segment_creation=false

Restart the oracle service.

Show parameter deferred_segment_creation

NAME TYPE VALUE

-

Deferred_segment_creation boolean TRUE

SQL > alter system set deferred_segment_creation=false

The system has changed.

SQL > show parameter deferred_segment_creation

NAME TYPE VALUE

-

Deferred_segment_creation boolean FALSE

The default value of this parameter is TRUE, and when changed to FALSE, segment is assigned to both empty and non-empty tables.

It should be noted that this value has no effect on the previously imported empty tables and still cannot be exported, but can only have an effect on the newly added tables. If you want to export a previous empty table, you can only use the first method.

After messing with me for a long time, I finally found this method.

First query all the empty tables under the current user

Select table_name from user_tables where NUM_ROWS=0

Use the following sentence to find an empty table

Select 'alter table' | | table_name | | 'allocate extent;' from user_tables where num_rows=0 or segment_created='NO'

Export the query results and execute the exported statement

'ALTERTABLE' | | TABLE_NAME | | 'ALLOCATEEXTENT;'

Vs.

Expdp error: ora-39127 "WMSYS"

Reason:

LT_EXPORT_PKG should be in SYS mode before 10.2.0.4, but after 10.2.0.4, the package has been moved to WMSYS mode.

Check the contents of the EXPPKGACT$

Select * from sys.exppkgact$ wherepackage='LT_EXPORT_PKG'

Solution:

Create table sys.exppkgact$_backup asselect * from sys.exppkgact$;-back up the table

Delete fromsys.exppkgact$ where package = 'LT_EXPORT_PKG';-- Delete the data whose table interior value is LT_EXPORT_PKG

At this point, I believe you have a deeper understanding of "exp error reporting and why exp can not derive some table structure reasons". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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