You can configure in-server soft locking of database rows
used by EJB CMP entity beans that use the isolation level repeatable_read_with_cache.
If you enable soft locking for a component, EAServer applies a soft lock to each row selected by an instance, which prevents other component instances running in the server from updating the row. Soft locking must be used with optimistic concurrency control (OCC). The soft lock prevents update collisions between instances in the same server, while OCC prevents update collisions with external applications and instances running in another server.
You can enable soft locking by setting the following component properties:
com.sybase.jaguar.component.softLock – a value of true enables soft locking. The default of false disables soft locking.
com.sybase.jaguar.component.softLock.timeout – the timeout period for soft-locked rows, specified in seconds. Soft locks use a timeout mechanism to avoid deadlock. The default is 5. If too many “soft lock timeout” errors are reported in the server log, increase the timeout.
As an alternative to pessimistic locking, OCC with soft locking may improve performance if there is heavy update contention among entity bean instances running in a single-server deployment or in small-to-medium sized clusters. In clusters, if you see excessive OCC update failures, you may need to switch to pessimistic database locking as described in “Enabling PCC”.
