IO function metric.
Date: Tue, 23 Dec 2008 13:22:01 +0000 (UTC)
Oracle 11g has a table called V$IOFUNCMETRIC which is a typical metric table, like the set that was introduced in 10g. What confuses me are 2 things:
1) SQL> select function_name from V$IOFUNCMETRIC;
Buffer Cache Reads
RMAN 13 rows selected.
What the heck is "smart scan"? It's neither a buffer cache read nor a direct read since both functions are defined separately.
2) 1 select SMALL_READ_MBPS,SMALL_READ_IOPS
2 from V$IOFUNCMETRIC
3* where FUNCTION_NAME='LGWR'
SQL> / SMALL_READ_MBPS SMALL_READ_IOPS
LGWR is READING? What is log writer reading? Log writer is not supposed to be reading anything. Why is LGWR doing reads? I consider it to be cheating. Does anybody have any information as to what is LGWR reading? Kevin Closson's explanation from this article http://tinyurl.com/yr37pw obviously does not cover this case.
-- Mladen Gogala http://mgogala.freehostia.comReceived on Tue Dec 23 2008 - 07:22:01 CST