Depending on the database workload, you might want to use source-side,
target-side, or full pushdown optimization at different times. For example, use
source-side or target-side pushdown optimization during the peak hours of the
day, but use full pushdown optimization from midnight until 2 a.m. when
database activity is low.
To use different pushdown optimization configurations at
different times, use the $$PushdownConfig mapping parameter. The parameter lets
you run a session using the different types of pushdown optimization. The
settings in the $$PushdownConfig parameter override the pushdown optimization
settings in the session properties.
Complete the following steps to configure the mapping
parameter:
1.
Create $$PushdownConfig in the Mapping Designer.
2.
When you add the $$PushdownConfig mapping
parameter in the Mapping Designer, use the following values:
Field
|
Value
|
Name
|
$$PushdownConfig
|
Type
|
Parameter
|
Datatype
|
String
|
Precision
or Scale
|
20
|
Aggregation
|
n/a
|
Initial
Value
|
None
|
Description
|
Optional
|
3.
When
you configure the session, select $$PushdownConfig for the Pushdown
Optimization attribute.
4.
Define
the parameter in the parameter file
Enter
one of the following values for $$PushdownConfig in the parameter file:
Value
|
Description
|
None
|
Integration
Service processes all transformation logic for the session.
|
Source
[Seq View Conn]
|
Integration
Service pushes as much of the transformation logic to the source database as
possible.
|
Target
[Seq View Conn]
|
Integration
Service pushes as much of the transformation logic to the target database as
possible.
|
Full
[Seq View Conn]
|
Integration
Service pushes as much of the transformation logic to the source and target
databases as possible. The Integration Service processes any transformation
logic that it cannot push to a database.
|
Optionally,
specify one or more of the following options:
Seq.
Allows the Integration Service to create a sequence object in the database.
View.
Allows the Integration Service to create a view object in the database.
Conn.
Indicates that the database user of the active database has read permission on
the idle database, which is required to push transformation logic to the active
database.
For
example, enter ‘Full View Conn’ to use full pushdown optimization, enable the
creation of view objects in the active database, and indicate that the active
database has read permission on the idle database.
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