Re: phyrds in v$filestat and sql trace not match !!

My guess will be that PHYRDS is the count of start i/o's. Each start i/o read mutilblock_read_count blocks from the disk. The data buffer that you read with each start i/o is the same: 8 blocks of 8k or 16 blocks of 4k. So you get the same number of start i/o's.

Yechiel Adar
Mehish
----- Original Message -----
To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com> Sent: Tuesday, November 12, 2002 12:43 PM

> list,
> i'm doing benchmarking using two DB's with different block size
> i run a count(*) on a 17 million row table, and compare the sql_trace file
> and the v$filestat stats..
> the db was bounced before each test, the init.ora params were identical,
> EXCEPT
> in DB1 (4k block size) the muldiblock read was 16, and DB2(block size 8k)
it
> was 8
>
> 4 samples were taken...
>
> CPU time :
> DB1 = 9023
> DB2 = 8027
>
> elapsed time:
> DB1 = 19171
> DB2 = 18045
>
> phy reads: (from sql_trace)
> DB1 = 327022
> DB2 = 159347
>
> PHYRDS from v$filestat
> DB1 = 16386
> DB2 = 16385
>
> PHYBLKRDS from v$filestat
> DB1 = 262148
> DB2 = 131073
>
> my question is... why the physical reads in the v$filestat are equal ??
but
> the p reads in the sql_trace
> file are different ??
>
> TIA
> rahul
>
>
>
>
>
>
>
>
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> --
> Author: Rahul
> INET: rahul_at_ratelindo.co.id
>
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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Yechiel Adar
  INET: adar76_at_inter.net.il

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