Oracle 11g export using EXP utility missing some tables

Problem:-

I have recently exported a 11g schema using 11g EXP utility and tried to import into another 11g Instance using 11g IMP utility. But, not all the tables got transferred to the destination instance. On further debugging, I found out that empty tables i.e. tables with NO ROWS (0 rows) did not get exported to dump thus they were missing.

Cause:-

This is due to oracle feature "Segment creation on Demand (Deferred Segment Creation).

Solution:-

1) Use the new Oracle Data Pump utilities for the export and import: expdp/impdp instead of exp/imp

2) Turn off the Oracle feature before creating any object

ALTER SYSTEM SET DEFERRED_SEGMENT_CREATION=FALSE;

3) Force the allocation of extents on each empty table using the following command

ALTER TABLE <table_name> ALLOCATE EXTENT;

Re-run the export EXP command, which would export the empty tables as well.

Comments

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