Re: High query cost but low execution time
Date: Mon, 16 Apr 2012 12:03:46 -0700 (PDT)
Message-ID: <1334603026.33181.YahooMailNeo_at_web121001.mail.ne1.yahoo.com>
No, the cost is not a true representative of time and cost is not *everything*. If no one is complaining and you are happy with the performance, I would not concern myself with the cost that is being reported. Thanks!
Kellyn Pot'Vin
Senior Technical Consultant
Enkitec
DBAKevlar.com
From: "Hameed, Amir" <Amir.Hameed_at_xerox.com> To: oracle-l_at_freelists.org
Sent: Monday, April 16, 2012 12:54 PM
Subject: High query cost but low execution time
Hi,
I have a statement which produces a high CBO cost but executes very
quickly, as shown below. Based on the execution timings, is the cost
figure a true representative of the response time? The DB version is
11.1.0.7.
Thanks
Amir
call count cpu elapsed disk query current rows
- ------ -------- ---------- ---------- ---------- ----------
Parse 1 0.08 0.08 0 10 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 54 0.82 0.79 0 18922 0 788
- ------ -------- ---------- ---------- ---------- ----------
total 56 0.90 0.87 0 18932 0 788
Rows Row Source Operation
------- ---------------------------------------------------
788 HASH GROUP BY (cr�017 pr=0 pw=0 time=7 us costs709 size08608 card224)
2633 NESTED LOOPS (cr932 pr=0 pw=0 timeW2 us costs403 size08608 card224)
2633 NESTED LOOPS (cr593 pr=0 pw=0 timeI5 us costY169 size37920 card224)
2633 NESTED LOOPS (cr�36 pr=0 pw=0 time46 us cost0699 sizeh2752 card224)
2633 NESTED LOOPS (cr79 pr=0 pw=0 time6 us cost 19 size_at_1212 card329)
1 NESTED LOOPS (cr pr=0 pw=0 time=0 us cost size card=1)
1 VIEW VW_SQ_1 (cr pr=0 pw=0 time=0 us cost=8 size=4 card=1)
1 HASH UNIQUE (cr pr=0 pw=0 time=0 us)
1 HASH JOIN (cr pr=0 pw=0 time=0 us cost=8 size5 card=1)
1 TABLE ACCESS BY INDEX ROWID XMAF_GEN_INT_PARAMS (cr=2 pr=0 pw=0 time=0 us cost=2 size' card=1)
1 INDEX RANGE SCAN PG_IDX1 (cr=1 pr=0 pw=0 time=0 us cost=1 size=0 card=1)(object id 4486804)
215 TABLE ACCESS FULL MTL_PARAMETERS (cr pr=0 pw=0 time=4 us cost=5 size20 card!5)
1 TABLE ACCESS BY INDEX ROWID MTL_PARAMETERS (cr=2 pr=0 pw=0 time=0 us cost=1 size=8 card=1)
1 INDEX UNIQUE SCAN MTL_PARAMETERS_U1 (cr=1 pr=0 pw=0 time=0 us cost=0 size=0 card=1)(object id 7243)
2633 TABLE ACCESS BY INDEX ROWID MTL_ONHAND_QUANTITIES_DETAIL (cr59 pr=0 pw=0 time1 us cost 10 size"9264 card3
29)
2633 INDEX RANGE SCAN MTL_ONHAND_QUANTITIES_N8 (cr pr=0 pw=0 time us costV size=0 card329)(object id 3695328)
2633 TABLE ACCESS BY INDEX ROWID MTL_SYSTEM_ITEMS_B (cru57 pr=0 pw=0 time=0 us cost=2 size card=1)
2633 INDEX UNIQUE SCAN MTL_SYSTEM_ITEMS_B_U1 (crR18 pr=0 pw=0 time=0 us cost=1 size=0 card=1)(object id 7343)
2633 TABLE ACCESS BY INDEX ROWID MTL_SYSTEM_ITEMS_B (cru57 pr=0 pw=0 time=0 us cost=2 size2 card=1)
2633 INDEX UNIQUE SCAN MTL_SYSTEM_ITEMS_B_U1 (crR18 pr=0 pw=0 time=0 us cost=1 size=0 card=1)(object id 7343)
--
http://www.freelists.org/webpage/oracle-l
--
http://www.freelists.org/webpage/oracle-l
Received on Mon Apr 16 2012 - 14:03:46 CDT