DBD ERROR: OCISessionBegin

Here is a quick workaround you can use to get an instance back-up an open for business if you are running into these types of Oracle errors and users cannot log-in to the system:


ERROR:
ORA-04031: unable to allocate 4064 bytes of shared memory ("shared
pool","update seq$ set increment$=:...","sga heap(1,0)","kglsim heap")

Or maybe:

ORA-00604: error occurred at recursive SQL level 1

ORA-04031: unable to allocate 2336 bytes of shared memory ("shared pool","unknown object","sga heap(1,1)","ksv work msg") (DBD ERROR: OCISessionBegin)

SQL> ALTER SYSTEM FLUSH SHARED_POOL;

Note:  Taking this action will get rid of everything stored in the shared pool.  This will affect you hard/soft parse ratios.

This of course will not correct the underlying issue, but it will allow you to get the instance open quickly.  Then you can go looking for the offender(s).