A relational source might produce data that is not the same or in the same order between workflow runs. When you configure recovery to resume from the last checkpoint, the Integration Service stores the SQL result in a cache file to guarantee the output order for recovery.
If you know the SQL result will be the same between workflow runs, you can configure the source qualifier to indicate that the data is repeatable and deterministic. When the relational source output is deterministic and the output is always repeatable, the Integration Service does not store the SQL result in a cache file. When the relational output is not repeatable, the Integration Service can skip creating the cache file if a transformation in the mapping always produces ordered data.