Data Pump Import (invoked with the impdp command) is a new utility as of Oracle This parameter is valid only in the Enterprise Edition of Oracle Database 10g. . expdp SYSTEM/password SCHEMAS=hr DIRECTORY=dpump_dir1. Either run IMP once OR export the 10 schemas to 10 separate files, and imp the 10 2) yes, that is what it is programmed to do (impdp – datapump – is more. For example, if one database is Oracle Database 12c, then the other database must be 12c, 11g, or 10g. Note that Data Pump checks only the major version.
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Oracle Data Pump technology enables very high-speed movement of data and metadata from one database to another. Oracle Data Pump is available only on Oracle Database 10g release 1 They provide a user interface that closely resembles the original export exp and import imp utilities.
These parameters enable the exporting and importing of data and metadata for a complete database or subsets of a database. When data is moved, Data Pump automatically uses either im;dp path load or unload or the external tables mechanism, or a combination impfp both.
The new Data Pump Export and Import utilities invoked with the expdp and impdp commands, respectively have a similar look and feel to the original Export exp and Import imp expsp, but they are completely separate. Dump files generated by the new Data Pump Export utility are not compatible with dump files generated by the original Export utility. Therefore, files generated by the original Export exp utility cannot be imported with the Data Pump Import impdp utility.
Original Export and Import support the full set of Oracle database release 9. Also, the design of Data Pump Export and Import results in greatly enhanced data movement performance over the original Export and Import utilities. The following are the major new features that provide this increased performance, as well as enhanced kracle of use:.
The ability to specify the maximum number oarcle threads of active execution operating on behalf of the Data Pump job. This enables you to adjust resource consumption versus elapsed time. This feature is available only in the Enterprise Edition of Oracle Database 10 g.
The ability to restart Data Pump jobs. The ability to detach from and reattach to long-running jobs without affecting the job itself. This allows DBAs and other operations personnel to monitor jobs from multiple locations. The Data Pump Export and Import utilities can be attached to only one espdp at a time; however, you can have multiple clients or jobs running at one time. If you are using the Data Pump API, the restriction on attaching to only one job at a time does lracle apply. You can also have multiple clients attached to the same exldp.
Support for export and import operations over the network, in which the source of each operation is a remote instance. The ability, in an import job, to 10b the name of the source datafile to a different name in all DDL statements where the source datafile is referenced.
Enhanced support for remapping tablespaces during an import operation. Support for filtering the metadata that is exported and imported, based upon objects and object types. Support for an interactive-command mode that allows monitoring of and interaction with ongoing jobs. The ability to estimate how much space an export job would consume, without actually performing the export.
Exporting and Importing Between Different Database Releases
The ability to specify the version of database objects to be moved. Most Data Pump export and import operations occur on the Oracle database server. This contrasts with original export and import, which were primarily client-based. The remainder of this chapter discusses Data Pump technology as it is implemented in the Data Pump Export and Import utilities.
To make full use of Data Pump technology, you must be a privileged user. Nonprivileged users have neither. Export and import nonschema-based objects such as tablespace and schema definitions, system privilege grants, resource plans, and so forth. Data Pump supports two access methods to load and unload table row data: Because both methods support the same external data representation, data that is unloaded with one method can be loaded using the other method.
Data Pump automatically chooses the fastest method appropriate for each table. The Oracle database has provided direct path unload capability for export operations since Oracle release 7. Data Pump technology enhances direct path technology in the following ways:. Improved performance through elimination of unnecessary conversions.
This is possible because the direct path internal stream format is used as the format stored in the Data Pump dump files. The default method that Data Pump uses for loading and unloading data is direct path, when the structure of a table allows it. Note that if the table has any columns of datatype LONGthen direct path must be used. The following sections describe situations in which direct path cannot be used for loading and unloading. If any of the following conditions exist for a table, Data Pump uses external tables rather than direct path to load the data for that table: A global index on multipartition tables exists during a single-partition load.
This includes object tables that are partitioned.
The table into which data is being imported is a pre-existing table and at least one of the following conditions exists:. If any of the following conditions exist for a table, Data Pump uses the external table method to unload data, rather than direct path:. The table contains one or more columns of type BFILE or opaque, or an object type containing opaque columns.
The Oracle database has provided an external tables capability since Oracle9 i that allows reading of data sources external to the database. Expdpp of Oracle Database 10 gthe external tables feature also supports writing database data to destinations external to the database. The format of the files is the same format used with the direct path method. This allows for high-speed loading and unloading of database tables. Data Pump uses external tables as the data access mechanism in the following situations:.
Loading and unloading very large tables and partitions in situations where parallel SQL can be used to advantage. Loading tables with global or domain indexes defined on them, including partitioned object tables. When you perform an export over a database link, the data from the source database instance is written to dump files on the connected database instance. In addition, the source database can be a read-only database. When you perform an inpdp over a database link, the import source is a database, not a dump file set, and the data is imported to the connected database instance.
Because the link can identify a remotely networked database, the terms database link and network link expep used interchangeably.
Data Pump jobs use a master table, a master process, and worker processes to perform the work and keep track of progress. The master process ex;dp the entire job, including communicating with the clients, creating and controlling a pool of worker processes, and performing logging operations. While the data and metadata are being transferred, a master table is used to track the progress within a job. The master table is implemented as a user table within the database.
The specific function of the master table for export and import jobs is as follows:. For export jobs, the master table records the location of database objects within a dump file set. Export builds and maintains the master table for the duration of the job.
At the end of an export job, the content of the master table is written to a file in the dump file set. For import jobs, the master table is loaded from the dump file set and is used to control the sequence of operations for locating objects that need to be imported into the target database. The master table is created in the schema of the current user performing the export or import operation. Therefore, that user must have sufficient tablespace quota for its creation.
The name of exdp master table is the same as the name of the job that created it. Therefore, you cannot explicitly give a Data Pump job the same name as a preexisting table or view. If a job terminates unexpectedly, the master table is retained. You can delete it if you do not intend to restart the job. If immpdp job stops before it starts running that is, it is in the Defining statethe master table is dropped.
Within the master table, specific objects are assigned attributes such as name or owning schema. The class of an object is called its object type. The objects can be based upon the name of the object or the name of the schema that owns the object. You can also specify data-specific filters to restrict the rows that are exported and imported.
When you are moving data from one database to another, it is often useful to perform transformations on the metadata for remapping storage between tablespaces or redefining the owner of a particular set of objects. This is done 110g the following Data Pump Import parameters: For example, to limit the effect of a job on a production system, the database administrator Orace might wish to restrict the parallelism.
The degree of parallelism can be reset at any time during a job.
For example, PARALLEL could be set to 2 during production hours to restrict a particular job to only two degrees of parallelism, and during nonproduction hours it could be reset to 8.
The parallelism setting is enforced by the master process, which allocates work to be executed to worker processes that perform the data and metadata processing within an operation. These worker processes operate in parallel. In general, the degree of parallelism should be set to more than twice the number of CPUs on an instance. The worker processes are the ones that actually unload and load metadata and table data in parallel.
The number of active worker processes can be reset throughout the life of a job.
Data Pump Import
When a worker process is assigned the task of loading or unloading a very large table or partition, it may choose to use the external tables access method to make maximum use of parallel execution. In such a case, the worker process becomes a parallel execution coordinator. The Data Pump Export and Import utilities can be attached to a job in either interactive-command mode or logging mode.
In logging mode, real-time detailed status about the job is automatically displayed during job execution. The information displayed can include the job and parameter descriptions, an estimate of the amount of data to be exported, a description of the current operation or item being processed, files used during the job, any errors encountered, and the final job state Stopped or Completed.
Job status can be displayed on request in interactive-command mode. The information displayed can include the job description and state, a description of the current operation or item being processed, files being written, and a cumulative status. A log file can also be optionally written during the execution of a job. The log file summarizes the progress of the job, lists any errors that were encountered along the way, and records the completion status of the job.