By default, the Maximum size (in bytes) of incoming HTTP requests (POST) that the Web server is authorized to process is a little less than 2Mb (2,000,000 bytes). In practice, it means that no limit is set. If you want to limit the maximum size of incoming requests, you can do so using the SET DATABASE PARAMETER command with the selector 27 (Maximum Web requests size). You can use values from 500, 000 to 2 147 483 648 bytes. When a request, whose size is over this value, is received, by 4D, it is denied.
This limit is used to avoid Web server saturation due to incoming requests that are too large.