Use pass-through partitioning at the source qualifier.

Use single- or multi-threaded reading with flat file or COBOL sources.

Use single-threaded reading with XML sources.

You cannot use multi-threaded reading if the source files are non-disk files, such as FTP files or WebSphere MQ sources.

If you use a shift-sensitive code page, use multi-threaded reading if the following conditions are true:

To read data from the three flat files concurrently, you must specify three partitions at the source qualifier. Accept the default partition type, pass-through.

If you configure a session for multi-threaded reading, and the Integration Service cannot create multiple threads to a file source, it writes a message to the session log and reads the source with one thread.

When the Integration Service uses multiple threads to read a source file, it may not read the rows in the file sequentially. If sort order is important, configure the session to read the file with a single thread. For example, sort order may be important if the mapping contains a sorted Joiner transformation and the file source is the sort origin.

You can also use a combination of direct and indirect files to balance the load.

Session performance for multi-threaded reading is optimal with large source files. The load may be unbalanced if the amount of input data is small.

You cannot use a command for a file source if the command generates source data and the session is configured to run on a grid or is configured with the resume from the last checkpoint recovery strategy.