Automatic Record Lock Timeout

In a multi-user environment where files are being shared, programs use record locks to control concurrent access to individual records. In addition, Fileshare automatically obtains a record lock on any record that it updates within a transaction. The larger the number of record locks being held, however, the less concurrent access to data is possible. It is beneficial, therefore, for any one program to keep the number of record locks that it holds at any one time to a minimum.

If a Fileshare Client obtains a lock on a record (either explicitly or because it updated the record within a transaction) and a second Fileshare Client tries to read the locked record, the Fileshare Server checks to see how long it is since the Fileshare Client holding the record lock last contacted the Fileshare Server. If this period is:

• Greater than the timeout period, the Fileshare Server:
  • Automatically rolls back any pending transaction being carried out by the first Fileshare Client
  • Releases all the record locks held by the first Fileshare Client
  • Returns error 9/068 "record locked" to the Client trying to read the record. Retrying the operation succeeds in gaining access to the record because the lock has now been released.
• Less than the timeout period, the Fileshare Server returns error 9/068 "record locked" to the Fileshare Client trying to read the record

The default timeout period is 60 seconds. You can change this value using the /t option in the Fileshare Server configuration file. Specifying a value of zero disables the automatic record lock timeout such that record locks are only released under application program control.

A program that is timed out receives error 9/125 on its next I/O operation. You should treat this as a warning message and repeat the operation on which the error was returned. The Fileshare Server rolls back any active transaction and releases all the record locks held by the program that timed out.