No resources currently available in pool SOADataSource to allocate to applications error

Error stack-trace:

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)

Error Cause:

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.

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

1. ActiveConnectionsAverageCount
2. ActiveConnectionsCurrentCount

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.When any data source will not be responding then it's state will be overloaded.

Solution :- 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.