Don't worry about hit rate. The BOOK "performance tuning 101" said "hit
rate" is NOT important.



On Tue, 31 Jul 2001, Schoen Volker wrote:

> increase db_block_buffers in init.ora and check SQL-Statements with most
> physical reads.
>
> Regards
>
> Volker Schön
> E-Mail: mailto:v.[Email Address Removed] http://www.inplan.de
>
>
>
> -----Ursprüngliche Nachricht-----
> Von: Khan, Majid [mailto:majid.[Email Address Removed] Gesendet: Dienstag, 31. Juli 2001 14:42
> An: LazyDBA.com Discussion
> Betreff: my buffer cache hit ratio is 63.63? any recommendation?
>
>
> hi dba's
> my buffer hit ratio is 63.63 but my user hit ratio is about 99%
> I need to tune my database is there any recommendation from you guys
>
>
>
> SELECT Sum(DECODE(name, 'consistent gets', value, 0)) AS "consistent_gets",
> Sum(DECODE(name, 'db block gets', value, 0)) AS "db_block_gets",
> Sum(DECODE(name, 'physical reads', value, 0)) AS "physical_reads",
> TO_CHAR(
> (
> Sum(DECODE(name, 'consistent gets', value, 0))
> + Sum(DECODE(name, 'db block gets', value, 0))
> - Sum(DECODE(name, 'physical reads', value, 0))
> )
> /
> (
> Sum(DECODE(name, 'consistent gets', value, 0))
> + Sum(DECODE(name, 'db block gets', value, 0))
> )
> * 100, '99999999.99' ) AS "hit_ratio, %"
> FROM v$sysstat;
>
> --------------------------------------------------------------------------
>
> consistent_gets db_block_gets physical_reads hit_ratio, %
> --------------- ------------- -------------- ------------
> 15744863 783286 6011121 63.63
>
> --------
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