Expert Oracle Exadata - Parent Directory

CHAPTER 13 MIGRATING TO EXADATAREMAP_SCHEMA: As the name implies, this parameter tells Data Pump to changethe ownership of objects from one schema to another during the course of theimport. This is particularly useful for resolving schema conflicts when mergingmultiple databases into one Exadata database.REMAP_DATAFILE: Datafiles can be renamed dynamically during the importprocess using this parameter. This allows ASM to automatically organize andname the datafiles according to Oracle Managed Files (OMF) rules.REMAP_TABLESPACE: This option changes the tablespace name reference forsegments from one tablespace to another. It is useful when you want tophysically relocate tables from one tablespace to another during the import.SCHEMAS: List of schemas to import.SQLFILE: Instead of importing anything into the database, Object definitions(DDL) are written to an SQL script. This can be quite useful for pre-buildingobjects if you want to make changes to their physical structure, such aspartitioning or using HCC compression.TABLE_EXISTS_ACTION: The action to take if the imported object already exists.Valid keywords are APPEND, REPLACE, [SKIP], and TRUNCATE.TABLES: A list of tables to import. For example, TABLES=KSO.SKEW, RJOHNSON.TESTTRANSFORM: This parameter allows you to make changes to segment attributes inobject-creation DDL statements, like storage attributes. This provides aconvenient way to optimize extent sizes for tables when they are created inExadata.Before you begin importing schemas into your Exadata database, be aware that Data Pump onlycreates tablespaces automatically when a full database import is done. So if you are importing at theschema or table level you will need to create your tablespaces manually. To do this, generate the DDL fortablespaces using the parameters FULL=yes and SQLFILE={your_sql_script}. This produces a script withthe DDL for all objects in the dumpfile, (including datafiles). One thing you may notice about the CREATETABLESPACE DDL is that the datafile file names are fully qualified. This isn’t at all what we want, because itcircumvents OMF and creates hard-coded file names that cannot be managed by the database. TheREMAP_DATAFILE parameter allows you to rename your datafiles to reflect the ASM disk groups in yourExadata database. The syntax looks something like this:REMAP_DATAFILE='/u02/oradata/LAB112/example01.dbf':'+DATA'One final note before we move on to Export/Import. Character set translation between the sourceand target databases is done automatically with Data Pump. Make sure the character set of the sourcedatabase is a subset of the target database, or something may be lost in translation. For example, it’sokay if your source database is US7ASCII (7 bit) and the target database is WE8ISO8859P1 (8 bit). Butmigrating between different 8-bit character sets or going from 8 bit to 7 bit may cause special charactersto be dropped.Export and ImportIf the database you are migrating to Exadata is a release prior to version 10g, Data Pump won’t be anoption. Instead you will need to work with its predecessors, Export (exp) and Import (imp).Export/Import features haven’t changed much since Oracle 9.2, but if you are migrating from a previous425