When you read data from a Microsoft SQL Server source, transform the data, and write the data to a target, you can configure

SQL ELT optimization

to push the transformation logic to the source or target database system. If the source and target databases are the same, you can configure full

SQL ELT optimization

for improved performance.

When the Secure Agent applies

SQL ELT optimization

, it pushes transformation logic to a database. The Secure Agent translates the transformation logic into SQL queries and sends the SQL queries to the database. The database runs the SQL queries to process the transformations.

SQL ELT optimization

improves mapping performance when the database can process the transformation logic faster than the Secure Agent. The Secure Agent also reads less data from the database.

The amount of transformation logic that the Secure Agent pushes to the database depends on the database, the transformation logic, and the

mapping

task. The Secure Agent processes all transformation logic that it cannot push to a database.

When you configure

SQL ELT optimization

for the mapping, the Secure Agent analyzes the optimized mapping from the source to the target or until it reaches a downstream transformation that it cannot push to the source database. The Secure Agent generates and executes a SELECT statement for each source that has transformation logic pushed down. Then, it reads the results of this SQL query and processes the remaining transformations in the mapping.

Full

SQL ELT optimization

is enabled by default in mapping tasks.

The Secure Agent can push the following transformation logic to a Microsoft SQL Server source: