The session waits on the buffer hash chain latch. Primarily used in the dump routines.

The virtual address in the SGA where this latch is located. Use the following statement to find the name of this latch:

select *
from v$latch a, v$latchname b
where addr = latch addr
and a.latch# = b.latch#;
chain#

The index into array of buffer hash chains. When the chain is 0xfffffff, the foreground waits on the LRU latch.