Database Software

I am on 11.1.0.7 and have enabled Automatic Memory management. We have also allocated 500MB to Streams Pool size. Here are the database parameters -

memory_max_target=25G
memory_target=25G
db_keep_cache_size=2500M
streams_pool_size=500M
sga_target = 15G
pga_aggregate_target = 2G


Although it started with 500MB but at one point, SGA got allocated 20G of memory out of total 25G but out of this 20G, 13G was allocated to streams_pool_size.

Looking at the views it looks like Shared pool needs more memory and streams is only using 13% of this 13G but still Streams is not dynamically giving back free memory to Shared pool.

Question -

Is this how Streams should be holding back memory and not releasing it back. If yes, how can I flush the memory back to SGA if I know the Streams is using just fraction of what it is holding.

Thanks!