Database Reference
In-Depth Information
For instance, if you want the tablespaces to be created at 20 percent of the original size, issue the following
command:
userid=mv_maint/foo
directory=dp_dir
dumpfile=inv.dmp
full=y
include=tablespace:"like '%DATA%'"
transform=pctspace:20
The tablespaces are created with data files 20 percent of their original size. The extent allocation sizes are also
20 percent of their original definition. This is important because Data Pump doesn't check to see if the storage
attributes meet the minimum size restrictions for data files. This means that if the calculated smaller size violates an
Oracle minimum size (e.g., five blocks for the uniform extent size), an error will be thrown during the import.
This feature is useful when used to export production data and then import it into a smaller database. In these
scenarios, you may be filtering out some of the production data via the
SAMPLE
parameter or
QUERY
parameters
(see the section “Filtering Data and Objects,” later in this chapter).
Changing Segment and Storage Attributes
When importing, you can alter the storage attributes of a table by using the
TRANSFORM
parameter. The general syntax
for this parameter is
TRANSFORM=transform_name:value[:object_type]
When you use
SEGMENT_ATTRIBUTES:N
for the transformation name, you can remove the following segment
attributes during an import:
•
Physical attributes
•
Storage attributes
•
Tablespaces
•
Logging
You may require this feature when you're importing into a development environment and don't want the tables
to come in with all the storage attributes as they were in the production database. For example, in development you
may just have one tablespace in which you store all your tables and indexes, whereas in production, you spread the
tables and indexes out in multiple tablespaces.
Here is an example that removes the segment attributes:
$ impdp mv_maint/foo directory=dp_dir dumpfile=inv.dmp \
transform=segment_attributes:n
You can remove just the storage clause by using
STORAGE:N
:
$ impdp mv_maint/foo directory=dp_dir dumpfile=inv.dmp \
transform=storage:n
