DP4 networking programs allow only a limited time for the server to reply. If no reply is received within the alloted time, a FAIL error 7 is generated, with an additional error code of 259. The default time-out is 10 seconds which should be sufficient in most circumstances, but there are situations where you may need to increase the value by using the -timeout number of seconds command tail.
If your program has transactions of unlimited size, a commit for an unusually big transaction may take too long, and cause a time-out. In this situation it is probably better to modify the program so that the transaction can be commited in smaller units (e.g. by using a status flag in a header record).
If you are using DP4 networking to connect to a Gateway ADC rather than a DP4 database certain fetch operations on big tabels may take an unusually long time because of the time taken by the SQL database to prepare a result set. This can cause a time-out. The AUXORACL ADC has an option that you can use to limit the size of a result set, but with the other ADCs you may need to increase the time-out.
If the time-out is increased the -timeout number of seconds command tail must be specified on both client and server programs, and the same value must be specified at both ends. If you use a different value you may well get spurious network errors.
Specify a reasonable value for the time-out. If you specify a value that it is too long, the users will probably reboot the machine or start pressing keys repeatedly, and it is probably better to get a time-out error before they lose patience.