No, Oracle does not scan empty blocks. It would be inefficient to do so.
"Bass Chorng" <bchorng_at_yahoo.com> wrote in message
news:bd9a9a76.0301201619.19d6d03f_at_posting.google.com...
> If I have a table with 0 rows but it has a very high highwater mark
> and if I do a select *, would Oracle scan all empty blocks into
> the buffer cache ?
>
> The known factor is Oracle will perform a full table scan to the
> highwater mark although the table is empty, and the question
> is,is Oracle going to flood the buffer cache with all the
> empty blocks it reads ?
>
> I don't see any reason why it wouldn't, as it is the same
> as if the table is loaded with rows. But then the state of
> x$bh would be 0 or 1 for those empty blocks that are read
> in ?
>
> I did a test and observed no state change. But I can not
> tell if it did not read the empty blocks in the first place
> or if it did, but since the blocks are empty, they are
> still marked as state 0.
>
> Wonder if any body knows the answer.
>
Received on Tue Jan 21 2003 - 18:28:29 CST
