DataPump Import (IMPDP) Seems To Hang When Importing Referential Constraints

(Doc ID 2308198.1)

Last updated on DECEMBER 06, 2017

Applies to:

Oracle Database - Enterprise Edition - Version 10.1.0.2 and later
Information in this document applies to any platform.

Goal

DataPump Import (impdp) is running slow when loading referential constraints:

Processing object type SCHEMA_EXPORT/TABLE/CONSTRAINT/REF_CONSTRAINT


The slowness of import when importing data with constraints enabled is introduced when validating the integrity of all existing data.

This behavior can introduce a serious performance problem when the amount of data to be checked is large and also there is a large number of constraints involved in this process.

The time spent on the ref_constraint load is directly proportional to the amount of data involved in the load operation.
Enabling the constraints in SQL*Plus or SQL*Loader will take same amount of time because by default, the constraint is created with "ENABLE VALIDATE" option;
VALIDATE ensures that existing data conforms to the constraint. So it is taking long time to validate the integrity of the constraint and appears to hang.

Solution

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