Given that a 1 GHz CPU can do about 100,000 logical I/Os per second, and the largest machine is currently (I think) only 128 CPUs, I can only guess three possibilities:
Your instance has been up for the last 500 years The statistics numbers don't match the ones that the Oracle code is supposed to match. You are running a 64-bit version of Oracle, and the code the exposes v$sysstat (or rather the x$ underlying it) is not quite in-line with the actual memory content. Jonathan Lewis http://www.jlcomp.demon.co.uk Host to The Co-Operative Oracle Users' FAQ http://www.jlcomp.demon.co.uk/faq/ind_faq.html Author of: Practical Oracle 8i: Building Efficient Databases -----Original Message----- To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> Date: 08 April 2002 16:15 |I am running the following (Oracle suggested - 8i) query to get the biffer hit ratio. This is our production Apps database. The numbers for logical and physical reads seem VERY high (especially phys_reads, which obviously causes our hit ratio to drop to 0). What could have caused this? | |SQL> list | 1 select A.value + B.value "logical_reads", | 2 C.value "phys_reads", | 3 D.value "phy_writes", | 4 (A.value+B.value)-C.value "log_minus_phys", | 5 round(100 * ((A.value+B.value)-C.value) / (A.value+B.value)) | 6 "Buffer Hit Ratio" | 7 from V$SYSSTAT A, V$SYSSTAT B, V$SYSSTAT C, V$SYSSTAT D | 8 where A.statistic# = 38 | 9 AND B.statistic# = 39 | 10 AND C.statistic# = 40 | 11* AND D.statistic# = 44 |SQL> / | | logical_reads phys_reads phy_writes log_minus_phys Buffer Hit Ratio |---------------------------- ---------------------------- ----------- ----- ---------------- ---------------- | 18,446,744,070,414,253,130 18,446,744,069,433,707,559 2,043,488 980,545,571 0 | |Here are some other stats; | |DTSTAMP PHYSICAL_READS DB_BLOCK_GETS CONSISTENT_GETS PHYSICAL_WRITES |-------------------- ---------------------------- ---------------- -- -------------------------- --------------- | PHYSICAL_READS_DIRECT PHYSICAL_WRITES_DIRECT SESSION_LOGICAL_READS |---------------------------- ---------------------- ----------------- ---- |08-APR-2002 10:35:16 18,446,744,069,434,437,169 171,781,916 18,446,744,070,280,471,598 2,103,859 | 18,446,744,047,946,114,866 966,679 1,032,014,671 |-- |Please see the official ORACLE-L FAQ: http://www.orafaq.com |-- | -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Jonathan Lewis INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- 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).
