Re: db file sequential read, where does it read to?

On 1 Nov 2006 13:28:20 -0800, "Ben" <balvey_at_comcast.net> wrote:

>9.2.0.5 Ent Ed AIX5L
>
>I've got a few long running processes that are all performing full
>table scans and they are waiting on db file % reads. When a file read
>is performed, is it reading the blocks into the buffer and then on to
>the user or does it just dump them straight out to the user? What I'm
>getting at is, Could these table scans be aging each other's blocks out
>of the buffer and thus causing more file reads?
>I guess if I could do away with the table scans in general that would
>solve my problem though...
>
>I hope that wasn't too confusing.
>

If, as the subject of your post suggest, you only see sequential reads and not scattered reads (or not a lot of it), you're not doing full table scans, your doing index range scans and table lookups from rowid's found in indexes.

Regards,
Jaap. Received on Fri Nov 03 2006 - 16:12:20 CST