Please see the "options for commands" section of this manual for general information about the use of macros for configuration.
By default this has a value of 2, the only other valid value is 4. It controls the size of a column in these tables:
With the default schema value of "2" you can only have up to 32,767 files in the MSI. If you change this value it may cause problems with merge modules.
This value is only applied when a table is created, so if the table already exists you need to delete the existing.
The performance section of this manual mentions compression of these files into a ".zip", ".cab" or similar archive file.