You are developing a SQL Server Integration Services (SSIS) package that loads data from a source transactional tables in a data warehouse. You discover that one of the data flows loads incorrect data

SSIS logging captures package events, warnings, row counts, and execution metadata but does not record or display the actual data values flowing through the data flow pipeline components.

A breakpoint pauses package or task execution at a defined event boundary for interactive debugging but does not expose the stream of row data flowing between individual data flow transformations.

A data viewer is attached directly to a data flow path connector in the SSIS designer and renders the actual rows of data as they pass between two components at runtime. By placing data viewers at successive points in the pipeline, a developer can compare input versus output data for each transformation and isolate exactly which component introduces the incorrect values. This targeted, row-level visibility makes it the most effective tool for diagnosing an incorrect data flow.

The locals window displays variable values and system property values during a breakpoint-suspended debug session but does not show the actual rows of data flowing through the data flow pipeline.