Data sampling is when Data Validation Option runs tests on a sample of data rather than the entire source. The PowerCenter Integration Service or a relational data source can generate the data sample.
By default, the PowerCenter Integration Service generates the data sample. The PowerCenter Integration Service reads all records from the source when it generates the data sample.
To increase run-time performance, you can configure IBM DB2, Microsoft SQL Server, Oracle, and Teradata to generate the data sample. After the database generates the data sample, the PowerCenter Integration Service reads the sample data only.