Some DBAs consider the large pool an optional feature for use only when you run a multithreaded server. But I have seen ORA-04031 and ORA-01037 errors that seemed to indicate insufficient shared-pool size when there were, in fact, megabytes of free pool. The errors went away when the large pool was used.
*Cause: More shared memory is needed than was allocated in the shared
pool.
*Action: If the shared pool is out of memory, either use the
dbms_shared_pool package to pin large packages,
reduce your use of shared memory, or increase the amount of
available shared memory by increasing the value of the
INIT.ORA parameters "shared_pool_reserved_size" and
"shared_pool_size".
If the large pool is out of memory, increase the INIT.ORA