Anjo,
Why do they appear in the first place?
Jared
Anjo Kolk <[EMAIL PROTECTED]>
Sent by: [EMAIL PROTECTED]
10/09/2002 09:09 AM
Please respond to ORACLE-L
To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]>
cc:
Subject: Re: Consistent gets
No problem as long as the stat "no work - consistent read gets"
(v$sysstat) is also close to that number.
Anjo.
Stephane Faroult wrote:
>
> Has anybody any idea why a query against tables on which very few if any
update are applied would display a high number of consistent gets ?
> Details : Big query involving 4/5 tables, most of them partitioned. This
is a test database, db block buffers about 100M, 5,000,000 of logical
reads with 8K blocks which means that the SGA is flushed a number of
times. The execution plan starts with a partition scan, then a series of
nested loops (hash join disappointing). The number of db block gets
corresponds to the number of blocks read during the partition scan;
everything else appears as consistent gets. You can rule out delayed
cleanout, since the same behaviour is displayed when the same query is run
over and over and not update at all takes place. Another curious symptom
is that the number of rows returned per second decreases by a factor 3 or
4 between the beginning and the end of the query. Believe me, no hideous
hidden scan of table of partition.
>
> TIA,
>
> Stephane Faroult
> Oriole
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