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 <[EMAIL PROTECTED]> 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: [EMAIL PROTECTED] > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com > San Diego, California -- Mailing list and web hosting services > --------------------------------------------------------------------- > To REMOVE yourself from this mailing list, send an E-Mail message > to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in > the message BODY, include a line containing: UNSUB ORACLE-L > (or the name of mailing list you want to be removed from). You may > also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Yechiel Adar INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).