Monday, August 13, 2007

Export/Import Pump - Copying Schemas

Let’s say that we have a Schema in Database A, which needs to be copied over to Database B. With the traditional export/import, we have to precreate the user account in the Database B, before we can import the schema. But with oracle10g’s Pump utility, it is just one simple step:

Here is an example. In this example, the schema CHANDRA exists in database A and we attempt to copy over the same schema as CHANDRA3 in a remote database (

$impdp system/******* schemas=chandra remap_schema=chandra:chandra3

Import: Release - Production on Saturday, 05 May, 2007 18:54:21

Copyright (c) 2003, 2005, Oracle. All rights reserved.

Connected to: Oracle Database 10g Enterprise Edition Release - Production

With the Partitioning, OLAP and Data Mining options

Starting “SYSTEM”.”SYS_IMPORT_SCHEMA_01″: system/******** schemas=chandra remap_schema=chandra:chandra3

Estimate in progress using BLOCKS method…


Total estimation using BLOCKS method: 0 KB

Processing object type SCHEMA_EXPORT/USER

Processing object type SCHEMA_EXPORT/SYSTEM_GRANT

Processing object type SCHEMA_EXPORT/ROLE_GRANT

Processing object type SCHEMA_EXPORT/DEFAULT_ROLE


Processing object type SCHEMA_EXPORT/TABLE/TABLE

Job “SYSTEM”.”SYS_IMPORT_SCHEMA_01″ successfully completed at 18:54:51

This creates the user CHANDRA3 as well in the remote/target database.

Don’t forget to provide different filenames when PARALLEL is used with Export Dump.

If you use PARALLEL option with Export Dump and fail to provide file names equal to the number of PARALLEL, then it would perform the export in serial - meaning writes to a single file.

For example, if you have something like this: $ expdp dumpfile=expdat.dmp directory=dump_dir parallel=4
It would create just one file with the name expdat.dmp. Instead you can specify some thing like:

$ expdp dumpfile=expdat.%U.dmp directory=dump_dir parallel=4

This would create 4 files in parallel with names (expdat.01.dmp, expdat.02.dmp, expdat.03.dmp..).


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