Advice on setting db_16k_cache_size for a new tablespace

11.2.0.1

Hi,

I want to create a new tablespace with 16k blocks. So we can create an index without hitting

ORA-00604: error occurred at recursive SQL level 1

ORA-01450: maximum key length (3215) exceeded

So, I found out that I need to set db_16k_cache_size.

But to how much? I guess its a MINIMAL threshold, so if I set to 64M it can grow bigger, but not lower then 64M?

Is there any way to find out a "good" size for the db_16k_cache_size?

EDIT: and it seems that not even a 32K tablespace was enough. Still hitting ORA-01450: maximum key length (3215) exceeded.