Performance: implicit cursors vs explicit

From: Bill Baker <bakerb_at_telusplanet.net>
Date: Sat, 06 Feb 1999 17:46:36 GMT
Message-ID: <36BC7961.22CDC69B_at_telusplanet.net>

Oracle uses 2 fetches when an implicit cursor is executed. Example:

select x
into i
from t
where z = y

The second fetch is used to determine if too_many_rows was issued. Explicit cursors perform better because the programmer issues the fetches and can do only 1.

However, if Oracle gets a query like so:

select x
into i
from t
where z = y
AND ROWNUM = 1 will it issue 1 or 2 fetches?

Thanks, and please copy me in email
Bill Received on Sat Feb 06 1999 - 18:46:36 CET