To improve performance, use physical files instead of source physical files for your data.
When a source physical file is used for stream I/O, the first 12 bytes of each record are not visible to your application. They are used to store the record number and update time. These 12 bytes are an extra load that the ILE C stream I/O functions must manipulate. For example:
Because the ILE C stream I/O functions dynamically create a source physical file when opening a text file that does not already exist for output, create the file as a physical file before you start your application.
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