Oracle SOA 11g – Skip locking for DBAdapter connection factories in clustered environments

Skip Locking is the new property introduced in 11g for the DBAdapter Connection factories. “In a distributed scenario, each polling instance will try to balance the load by not greedily attempting to process all unprocessed rows by itself. What that means is that at a time, an instance will only fetch at most MaxTransactionSize rows”. When using skip locking, if a full MaxTransactionSize rows are fetched, the next MaxTransactionSize rows can be immediately fetched continuously. This is because concurrent threads do no block each other when using skip locking. The Skip Locking offers performance benefits. However, with skip locking disabled, all threads will try to lock the same rows, and only one will succeed. Consequently, once this thread has processed MaxTransactionSize rows, it will pause until the next polling interval, to allow other threads to also lock and process rows. If we want to limit the number of records processed(MaxTransactionSize) in a particular polling interval then the SkipLocking should be disabled, the maximum throughput for each node with distributed polling enabled but uses SkipLocking disabled is: NumberOfThreads x MaxTransactionSize/PollingInterval