Hi

Cany anyone state a definition of Latch with a small example?
It seems to me like a latch is a block for memory structure as DML locks for data however I cant imagine how do latch protect the memory, in which way. DML lock is much easier to understand, when I update a row then that row is blocked. If this was with latch does it mean when i select some rows from data block buffer the rows i gather will be blocked to others but instead of a lock a latch? Latch is only present in SGA?

Cheers