* A relatively large object is defined by the instance parameter _shared_pool_reserved_min_alloc, which defaults to 4,400 bytes. Interesting, notice the default threshold value of 4,400 bytes is just larger than the typical single chunk request of 4,096 bytes. So, by default, Oracle is saying that any memory request larger than one typical size memory chunk request is to be considered large and therefore should get its memory from the reserved size.

Either of the first two parameters can be used to set the memory size exclusively reserved for the relatively large objects. If you set one of the parameters, Oracle calculates the other.5

By carefully adjusting these parameters, the performance analyst can increase the likelihood of a process finding a large amount of memory, while still maintaining plenty of memory of the relatively smaller objects. A report based on v$db_object_cache like the one shown earlier in Figure 7-14 can be very helpful to determine both the threshold size and the reserved memory size. While these parameters are typically not adjusted, if 4031 errors occur, their careful adjustment may fix the problem.