Re: Higher Consistent Gets...
You don't quote a version of Oracle - which makes
a difference to the ROWS column on the execution
path.
However, I think you are seeing the extra I/O because
Oracle is driving off the main table, then executing the
subquery for each row returned - thus executing your
5 logical I/O many times. Ideally you would probably
like Oracle to use the subquery to drive the main query.
You may be able to do this by converting the subquery
into an inline view, and joining it (perhaps with an ORDERED
hint) to the main query:
select /*+ ordered */
...
from
(
select location_code
from gn_location
connect by prior location_code=parent_code
start with location_code='3142'
)v
fr_search_query pd
where
pd.location_code = v.location_code
and
etc.
Jonathan Lewis
http://www.jlcomp.demon.co.uk
Host to The Co-Operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html
Author of:
Practical Oracle 8i: Building Efficient Databases
Screen saver or Life saver: http://www.ud.com
Use spare CPU to assist in cancer research.
-Original Message-
To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]>
Date: 14 September 2001 18:10
|!! Please do not post Off Topic to this List !!
|
|Hi
|
|I am having problem with a query. This query fetches rows from a
table which
|has 15 million rows.
|
|The problem is, when I execute this query with subquery, the
consistent gets
|are 4700. Where us without the subquery the consistent gets are just
400. If
|I execute the subquery alone, the consistent gets are just 5.
|
|
|Here is the main query with subquery results in cons.gets of 4700:
|
|
|select pd.holiday_id holidayID, pd.package_number l_package_number,
| min(pd.tfr_price) l_tpr_price
| from fr_search_query pd
| where pd.departure_date between TO_DATE('06/10/2001','dd/mm/')
| and TO_DATE('13/10/2001','dd/mm/')
| and pd.location_code in (select location_code
| from gn_location
|connect by prior
location_code=parent_code
| start with location_code='3142')
| and ROWNUM < 301
| group by pd.holiday_id , pd.package_number
| order by pd.location_name, pd.location_code, pd.accom_unit_name,
| pd.accom_unit_code, pd.departure_date,
min(pd.adult_price)
|
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--
Author: Jonathan Lewis
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RE: Higher Consistent Gets...
!! Please do not post Off Topic to this List !!
Try this and let's know how it works:
select --+ ordered use_hash(vw1)
pd.holiday_id holidayID, pd.package_number l_package_number,
min(pd.tfr_price) l_tpr_price
from fr_search_query pd ,
(select --+ no_merge
location_code
from gn_location
connect by prior location_code=parent_code
start with location_code='3142') vw1
where pd.departure_date between TO_DATE('06/10/2001','dd/mm/')
and TO_DATE('13/10/2001','dd/mm/')
and pd.location_code = vw1.location_code
and ROWNUM < 301
group by pd.holiday_id , pd.package_number
order by pd.location_name, pd.location_code, pd.accom_unit_name,
pd.accom_unit_code, pd.departure_date, min(pd.adult_price)
Regards,
Waleed
-Original Message-
Sent: Friday, September 14, 2001 8:10 PM
To: Multiple recipients of list ORACLE-L
!! Please do not post Off Topic to this List !!
Raj,
Which query is fastest? You don't have any timing information.
Make sure that timed_statistics is on in the database:
alter system set timed_statistics = true;
Run your query with trace on:
alter session set sql_trace = true;
Then run the resulting trace files through tkprof.
You'll have much more information to work with.
Jared
Raj Gopalan
ons.co.uk> cc:
Sent by: Subject: Higher
Consistent Gets...
[EMAIL PROTECTED]
09/14/01 09:55 AM
Please respond to
ORACLE-L
!! Please do not post Off Topic to this List !!
Hi
I am having problem with a query. This query fetches rows from a table
which
has 15 million rows.
The problem is, when I execute this query with subquery, the consistent
gets
are 4700. Where us without the subquery the consistent gets are just 400.
If
I execute the subquery alone, the consistent gets are just 5.
Here is the main query with subquery results in cons.gets of 4700:
select pd.holiday_id holidayID, pd.package_number l_package_number,
min(pd.tfr_price) l_tpr_price
from fr_search_query pd
where pd.departure_date between TO_DATE('06/10/2001','dd/mm/')
and TO_DATE('13/10/2001','dd/mm/')
and pd.location_code in (select location_code
from gn_location
connect by prior location_code=parent_code
start with location_code='3142')
and ROWNUM < 301
group by pd.holiday_id , pd.package_number
order by pd.location_name, pd.location_code, pd.accom_unit_name,
pd.accom_unit_code, pd.departure_date, min(pd.adult_price)
Trace results
Rows Execution Plan
--- ---
0 SELECT STATEMENT GOAL: CHOOSE
96 SORT (ORDER BY)
96SORT (GROUP BY)
96 COUNT (STOPKEY)
96 NESTED LOOPS
5137 INLIST ITERATOR
5138TABLE ACCESS GOAL: ANALYZED (BY INDEX ROWID) OF
'FR_SEARCH_QUERY'
8566 INDEX GOAL: ANALYZED (RANGE SCAN) OF
'FR_SEARCH_QUERY_IND_1' (NON-UNIQUE)
96 VIEW
5136SORT (UNIQUE)
1 CONNECT BY
2 INDEX GOAL: ANALYZED (FAST FULL SCAN) OF
'PK_GN_LOCATION' (UNIQUE)
1 TABLE ACCESS (BY USER ROWID) OF 'GN_LOCATION'
1 TABLE ACCESS (FULL) OF 'GN_LOCATION'
Running just the subquery results in cons.gets of just 5.
select location_code
from gn_location
connect by prior location_code=parent_code
start with location_code='3142'
Rows Execution Plan
--- ---
0 SELECT STATEMENT GOAL: CHOOSE
1 CONNECT BY
2INDEX GOAL: ANALYZED (UNIQUE SCAN) OF 'PK_GN_LOCATION'
(UNIQUE)
1TABLE ACCESS (BY USER ROWID) OF 'GN_LOCATION'
1TABLE ACCESS (RANGE SCAN) OF 'GN_PARENT_LOCATION_CODE'
(NON-UNIQUE)
Both the tables, indexes are analyzed. The optimizer mode is choose.
How do I tune this or Am I missing something obivious??
Thanks
Raj
--
Please see the official ORACLE-L FAQ: http://www.orafaq.com
--
Author: Raj Gopalan
INET: [EMAIL PROTECTED]
Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051
San Diego, California-- Public Internet access / Mailing Lists
To REMOVE yourself from this mailing list, send an E-Mail message
to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in
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(or the name of mailing list you want to be removed from). You may
also se
Re: Higher Consistent Gets...
!! Please do not post Off Topic to this List !!
Raj,
Which query is fastest? You don't have any timing information.
Make sure that timed_statistics is on in the database:
alter system set timed_statistics = true;
Run your query with trace on:
alter session set sql_trace = true;
Then run the resulting trace files through tkprof.
You'll have much more information to work with.
Jared
Raj Gopalan
ons.co.uk> cc:
Sent by: Subject: Higher Consistent
Gets...
[EMAIL PROTECTED]
09/14/01 09:55 AM
Please respond to
ORACLE-L
!! Please do not post Off Topic to this List !!
Hi
I am having problem with a query. This query fetches rows from a table
which
has 15 million rows.
The problem is, when I execute this query with subquery, the consistent
gets
are 4700. Where us without the subquery the consistent gets are just 400.
If
I execute the subquery alone, the consistent gets are just 5.
Here is the main query with subquery results in cons.gets of 4700:
select pd.holiday_id holidayID, pd.package_number l_package_number,
min(pd.tfr_price) l_tpr_price
from fr_search_query pd
where pd.departure_date between TO_DATE('06/10/2001','dd/mm/')
and TO_DATE('13/10/2001','dd/mm/')
and pd.location_code in (select location_code
from gn_location
connect by prior location_code=parent_code
start with location_code='3142')
and ROWNUM < 301
group by pd.holiday_id , pd.package_number
order by pd.location_name, pd.location_code, pd.accom_unit_name,
pd.accom_unit_code, pd.departure_date, min(pd.adult_price)
Trace results
Rows Execution Plan
--- ---
0 SELECT STATEMENT GOAL: CHOOSE
96 SORT (ORDER BY)
96SORT (GROUP BY)
96 COUNT (STOPKEY)
96 NESTED LOOPS
5137 INLIST ITERATOR
5138TABLE ACCESS GOAL: ANALYZED (BY INDEX ROWID) OF
'FR_SEARCH_QUERY'
8566 INDEX GOAL: ANALYZED (RANGE SCAN) OF
'FR_SEARCH_QUERY_IND_1' (NON-UNIQUE)
96 VIEW
5136SORT (UNIQUE)
1 CONNECT BY
2 INDEX GOAL: ANALYZED (FAST FULL SCAN) OF
'PK_GN_LOCATION' (UNIQUE)
1 TABLE ACCESS (BY USER ROWID) OF 'GN_LOCATION'
1 TABLE ACCESS (FULL) OF 'GN_LOCATION'
Running just the subquery results in cons.gets of just 5.
select location_code
from gn_location
connect by prior location_code=parent_code
start with location_code='3142'
Rows Execution Plan
--- ---
0 SELECT STATEMENT GOAL: CHOOSE
1 CONNECT BY
2INDEX GOAL: ANALYZED (UNIQUE SCAN) OF 'PK_GN_LOCATION'
(UNIQUE)
1TABLE ACCESS (BY USER ROWID) OF 'GN_LOCATION'
1TABLE ACCESS (RANGE SCAN) OF 'GN_PARENT_LOCATION_CODE'
(NON-UNIQUE)
Both the tables, indexes are analyzed. The optimizer mode is choose.
How do I tune this or Am I missing something obivious??
Thanks
Raj
--
Please see the official ORACLE-L FAQ: http://www.orafaq.com
--
Author: Raj Gopalan
INET: [EMAIL PROTECTED]
Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051
San Diego, California-- Public Internet access / Mailing Lists
To REMOVE yourself from this mailing list, send an E-Mail message
to: [EMAIL PROTECT
