ResourceLimitException : No resources currently available in pool to allocate to applications – Oracle SOA 11g

You could have observed the below exception frequently in the weblogic server log file, weblogic server throws the below exception when there is not enough database connections in the pool to serve the incoming requests reporting increasing the connection pool count. This will affect the overall system  performance java.sql.SQLException: Internal error: Cannot obtain XAConnection weblogic.common.resourcepool.ResourceLimitException: No resources currently available in pool SOADataSource to allocate to applications, please increase the size of the pool and retry.. at weblogic.common.resourcepool.ResourcePoolImpl.reserveResourceInternal(ResourcePoolImpl.java:577) at weblogic.common.resourcepool.ResourcePoolImpl.reserveResource(ResourcePoolImpl.java:342) at weblogic.common.resourcepool.ResourcePoolImpl.reserveResource(ResourcePoolImpl.java:329) at weblogic.jdbc.common.internal.ConnectionPool.reserve(ConnectionPool.java:417) at weblogic.jdbc.common.internal.ConnectionPool.reserve(ConnectionPool.java:324) The above exception is due to there is not enough connections available in the pool to service the requests. To identify which datasource / connection pool requires more connection do the following. Go to Weblogic Admin console Go to Environment -> Servers Select the server on which the connection pool needs to be monitored Go to Monitoring -> JDBC Customize the table to add the below two properties This page will list all the datasources/ connection pools targeted to that particular server and how many connections are waiting to get the connection. If more number of connections are waiting, that is not a good which will cause performance impact and also cause stuck threads on the server if the wait time is going to be beyond the thread stuck time (By default it's 10 mins). (This screen shot taken by reducing the max capacity to 5 for blogging purpose, unfortunately I did not captured the actual screen shot) Above screenshot shows SOADataSource state is "Overloaded" and also the current wait is 19. There are 19 resources waiting for connection . The above setup is definitely a problem which will result database calls performance issue. If the connection pool count is not increased with respect to the invoker thread count, then it will cause this kind of contention cause lot of calls to be waiting for connection. Solution to the above problem is to increase the number of connections in the connection pool. Steps: Go to WLS Console Select Services -> Datasources -> select the datasource you want to change the pool size Go to Configuration -> connection pool Change the Maximum Capacity to the count which is required for your environment.