This Happened recently when all of a sudden Database stopped responding.
Only option left was to bounce the DB. Since it is a RAC setup, we shutdown one of the instance first and fortunately after starting things came to normal.
Later on when i analyzed the AWR of Database, first instance i found ENQ:SQ contention in top events.
This was new for me, then i checked TOP SQL section of AWR.
Here all top queries were accessing a particular Sequence , when i checked this sequence it was newly created and the cache size was very less 10.
So as such i increased cache size to 100 initially, and till now things are working fine.
I think it was because of this particular sequence , and this should not occur again.
Will try to dig out more..about it...
Only option left was to bounce the DB. Since it is a RAC setup, we shutdown one of the instance first and fortunately after starting things came to normal.
Later on when i analyzed the AWR of Database, first instance i found ENQ:SQ contention in top events.
This was new for me, then i checked TOP SQL section of AWR.
Here all top queries were accessing a particular Sequence , when i checked this sequence it was newly created and the cache size was very less 10.
So as such i increased cache size to 100 initially, and till now things are working fine.
I think it was because of this particular sequence , and this should not occur again.
Will try to dig out more..about it...
