When working in simulation mode, the entire result set of the data source (as defined by a query in the source or staging component) can be divided into data blocks. A data block contains a subset of records. The number of records in each subset is related to the Read Block Size parameter in the Property section of the component. Choose a small number for the Read Block Size parameter to enhance the performance while stepping through the project.
To preview the result of a transformation
Step through the project including the component you want to preview.
Right-click the component, port, or the connecting Link.
Select the Preview command. If a component has multiple ports, select the port from the drop-down list.
