The error message "Unable to connect to datasource defds using a pooled database connection" appear very frequently on the as-server.log and as-summary.log.
What can I do?
Whenever you faced with the above problem, the usual step is to check on your java setting whether is it too low.
You may want to run the check the memory capacity of the Java by running the following command:-
/usr/jdk/latest/bin/jstat -gccapacity <PID ID of AS server>
NGCMN NGCMX NGC S0C S1C EC OGCMN OGCMX OGC OC PGCMN PGCMX PGC PC YGC FGC
393216,0 393216,0 393216,0 62400,0 46144,0 270464,0 655360,0 655360,0 655360,0 655360,0 16384,0 98304,0 61440,0 61440,0 1411 2459
If the OGCMN setting is too low, you may want to consider increase it by the instruction found at the following URL: http://www-01.ibm.com/support/docview.wss?uid=swg21609872
After increase the java setting and yet you still get the same error OR your setting of java is already too high and error still persist, then
1. Bounce the Application server ( sap stop AS ; sap start AS )
2. Contact IBM support.