This describes the sum of the data dictionary gets for objects. Here, there have been 409,000 total "gets" for dictionary objects.
This counts the number of times Oracle had to perform a disk I/O to retrieve a row from its dictionary tables. Here, there were 11,000 caches misses (where the object was once loaded, but had to be re-loaded since it was flushed from the pool).
This is the ratio of gets to get misses. Overall, the data dictionary cache hit ratio is 97%, which is quite acceptable.
The Data Dictionary gets Oracle metric is the total number of consistent gets (logical I/O) of the RAM data block buffer.
This alert looks at the Oracle data dictionary to compute data dictionary gets, data dictionary cache misses, and the data dictionary hit ratio,
and then alerts the DBA to times when requests for data dictionary metadata are high.
This problem can sometimes be relieved by increasing the shared_pool_size init.ora parameter, using the following syntax.