Why we use SQL override in Informatica?

SQL Override​ in Informatica​ We have an option to customize the default query provided by the transformations and enter custom SQL query by using SQL override. It then runs an SQL query against this view to push the transformation logic to the database.

What is lookup SQL override in Informatica?

When a mapping includes a Lookup transformation, the. mapping. task queries the lookup object based on the fields and properties that you configure in the Lookup transformation.

How can we improve the performance of SQL transformation in Informatica?

To optimize performance, do not use transaction statements in an SQL transformation query. Enable early selection or push-into filter optimization methods with the SQL transformation. To increase performance, the consider enabling the early selection or push-into optimization method with the SQL transformation.

Can we do SQL override in Joiner transformation?

Some of the difference between the Joiner transformation and Join of the SQL override in Source Qualifier transformation are the following: You can join heterogeneous data sources using the Joiner transformation which is not possible in a Source Qualifier transformation.

What is the difference between SQL override and lookup override?

The role of SQL Override is to limit the number of incoming rows entering the mapping pipeline, whereas Lookup Override is used to limit the number of lookup rows to avoid the whole table scan by saving the lookup time and the cache it uses. Lookup Override provides only Non-Equi joins.

Can we join two tables in lookup override?

10 Answers. Hi, We can join tables in Lookup SQL Override.

How do you handle performance issues in Informatica?

To improve the session performance, drop constraints and indexes before running the session (while loading facts and dimensions) and rebuild them after completion of the session. Parallel sessions: Running parallel sessions by using concurrent batches will also reduce the time of loading the data.

Which is better joiner or lookup in Informatica?

In case of Flat file, generally, sorted joiner is more effective than lookup, because sorted joiner uses join conditions and caches less rows. In case of database, lookup can be effective if the database can return sorted data fast and the amount of data is small, because lookup can create whole cache in memory.

What is the difference between lookup and joiner in Informatica?

Joiner is active transformation & lookup is passive transformation. Joiner transformation does not match for null values whereas lookup transformation matches for null values. >> Joiner will do left outer,right outer,normal,full outer types of joins whereas lookup will do only left outer join.

Can we use union in lookup override?

This behavior is seen when the SQL override was created with an initial SELECT clause that is not in the same order as the ports in the Lookup Transformation. Add the UNION clause to the generated SQL statement.

How is single lookup generated multiple tables?

Yes, you can use the main table for lookup. Table B col1 and then join it with table B with all the conditions required. Include those two columns which you want to lookup in lookup transformation. Then give the conditions in the lookup.

How can I improve my Iics performance?

General Guidelines to Improve Task Performance

1. Optimize the target. Enables the Secure Agent to write to the targets efficiently.
2. Optimize the source. Enables the Secure Agent to read source data efficiently.
3. Optimize the task.
4. Optimize the system.
5. Optimize the network.