hi
i have two questions...

1) when we try to retrieve data from a table...first cache is checked and then if not found
then it goes to disk for physicla read...right?
is this behaviour good that even if we need just a single row from a data block..whole block
or 4k or 8k is cached in the memory.....am i saying right??? is this the behaviour???

2) when a user performs a commit...the changed blocks are written permanently to disk at that
time or writing to disk happens just on check point ???

Regasrds