Re: fastest SQL?
- From: Martin Berger <martin.a.berger@xxxxxxxxx>
- To: Toon Koppelaars <toon@xxxxxxxxxxx>
- Date: Fri, 12 Mar 2010 08:52:12 +0100
I just tested the result cache for any effect (11gR1 on Sun-Blade-T6340,
Solaris10)
-- no_result_cache
alter system flush shared_pool;
System altered.
select SQL_ID, elapsed_time from v$sql
2 where sql_id = 'dtda63h3189hv';
no rows selected
select /* no_result_cache */ 1 from dual;
1
----------
1
select SQL_ID, elapsed_time from v$sql
2 where sql_id = 'dtda63h3189hv';
SQL_ID ELAPSED_TIME
------------- ------------
dtda63h3189hv 97707
select /* no_result_cache */ 1 from dual;
1
----------
1
select SQL_ID, elapsed_time from v$sql
2 where sql_id = 'dtda63h3189hv';
SQL_ID ELAPSED_TIME
------------- ------------
dtda63h3189hv 97707
-- result_cache
alter system flush shared_pool;
System altered.
select SQL_ID, elapsed_time from v$sql
2 where sql_id = 'f3cqkqf9272pp';
no rows selected
select /* result_cache */ 1 from dual;
1
----------
1
select SQL_ID, elapsed_time from v$sql
2 where sql_id = 'f3cqkqf9272pp';
SQL_ID ELAPSED_TIME
------------- ------------
f3cqkqf9272pp 32253
select /* berx1 */ 1 from dual;
1
----------
1
select SQL_ID, elapsed_time from v$sql
2 where sql_id = 'f3cqkqf9272pp';
SQL_ID ELAPSED_TIME
------------- ------------
f3cqkqf9272pp 32253
here, with and without result_cache the 2nd run of the statement is faster
than ELAPSED_TIME can show.
Does anyone know a better method to measure here?
On Thu, Mar 11, 2010 at 21:48, Martin Berger <martin.a.berger@xxxxxxxxx>wrote:
> Toon, Andre,
>
> can you test it, please?
> I'm not sure if the additional code and SGA access in result cache improves
> the query.
>
> (ok, we are now on a measurement issue: how can we measure such a fast sql?
> any good idea?)
>
>
>
> Am 11.03.2010 um 21:41 schrieb Toon Koppelaars:
>
> Any method to make it even faster?
>>
>
> Use the query result cache hint?
>
>
>
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