1Q. What are the differences between Connected and Unconnected Lookup?
The differences are illustrated in the below table| Connected Lookup | Unconnected Lookup |
| Connected lookup participates in dataflow and receives input directly from the pipeline | Unconnected lookup receives input values from the result of a LKP: expression in another transformation |
| Connected lookup can use both dynamic and static cache | Unconnected Lookup cache can NOT be dynamic |
| Connected lookup can return more than one column value ( output port ) | Unconnected Lookup can return only one column value i.e. output port |
| Connected lookup caches all lookup columns | Unconnected lookup caches only the lookup output ports in the lookup conditions and the return port |
| Supports user-defined default values (i.e. value to return when lookup conditions are not satisfied) | Does not support user defined default values |
2Q. What can we do to improve the performance of Informatica Aggregator Transformation?
Aggregator performance improves dramatically if records are sorted
before passing to the aggregator and "sorted input" option under
aggregator properties is checked. The record set should be sorted on
those columns that are used in Group By operation.
It is often a good idea to sort the record set in database level e.g. inside a source qualifier transformation, unless there is a chance that already sorted records from source qualifier can again become unsorted before reaching aggregator
It is often a good idea to sort the record set in database level e.g. inside a source qualifier transformation, unless there is a chance that already sorted records from source qualifier can again become unsorted before reaching aggregator
3Q.How can we update a record in target table without using Update strategy?
A target table can be updated without using 'Update Strategy'. For this,
we need to define the key in the target table in Informatica level and
then we need to connect the key and the field we want to update in the
mapping Target. In the session level, we should set the target property
as "Update as Update" and check the "Update" check-box.
4Q. Under what condition selecting Sorted Input in aggregator may fail the session?
- If the input data is not sorted correctly, the session will fail.
- Also if the input data is properly sorted, the session may fail if the sort order by ports and the group by ports of the aggregator are not in the same order.
5Q. What is the difference between Static and Dynamic Lookup Cache?
We can configure a Lookup transformation to cache the underlying lookup
table. In case of static or read-only lookup cache the Integration
Service caches the lookup table at the beginning of the session and does
not update the lookup cache while it processes the Lookup
transformation.
In case of dynamic lookup cache the Integration Service dynamically
inserts or updates data in the lookup cache and passes the data to the
target. The dynamic cache is synchronized with the target.
6Q. Why is Sorter an Active Transformation?
When the Sorter transformation is configured to treat output rows as
distinct, it assigns all ports as part of the sort key. The Integration
Service discards duplicate rows compared during the sort operation. The
number of Input Rows will vary as compared with the Output rows and
hence it is an Active transformation.
