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-- Copyright 2018 Tanel Poder. All rights reserved. More info at http://tanelpoder.com
-- Licensed under the Apache License, Version 2.0. See LICENSE.txt for terms & conditions.
--------------------------------------------------------------------------------
--
-- File name: lotslios.sql
-- Purpose: Generate Lots of Logical IOs for testing purposes
--
-- Author: Tanel Poder
-- Copyright: (c) http://www.tanelpoder.com
--
-- Usage: @lotslios <number>
-- @lotslios 100
-- @lotslios 1000000
--
-- Other: As the script self-joins SYS.OBJ$ to itself the maximum number
-- of rows processed (and LIOs generated) depends on the number
-- of rows in SYS.OBJ$
--
--------------------------------------------------------------------------------
prompt generate lots of LIOs by repeatedly full scanning through a small table...
select
/*+ monitor
leading(a b c)
use_nl(b) use_nl(c) use_nl(d)
full(a) full(b) full(c) full(d) */
count(*)
from
sys.obj$ a,
sys.obj$ b,
sys.obj$ c,
sys.obj$ d
where
a.owner# = b.owner#
and b.owner# = c.owner#
and c.owner# = d.owner#
and rownum <= &1
/