Oracle 的 v$sysmetric 中有两组物理 IO 指标？为什么？
two sets of physical IO metrics in Oracle's v$sysmetric?why?
我在 v$sysmetric 中发现了两组物理 IO 指标：一组在指标名称中有 "Total"，而另一组没有（例如，"Physical Read Total IO Requests Per Sec" 与 "Physical Read IO Requests Per Sec"）。有谁知道有什么区别？非常感谢。
我使用的Oracle DB：11.2.0.3.0 64bit，两个节点RAC
基于Oracle 12c Database Reference Statistics Descriptions，
不同之处在于 "total" 指标包括系统 activity，如备份和恢复，而另一个指标不包括。
physical read IO requests
Number of read requests for application activity (mainly buffer cache
and direct load operation) which read one or more database blocks per
request. This is a subset of "physical read total IO requests"
statistic.
physical read total IO requests
Number of read requests which read one or more database blocks for all
instance activity including application, backup and recovery, and
other utilities. The difference between this value and "physical read
total multi block requests" gives the total number of single block
read requests.
我在 v$sysmetric 中发现了两组物理 IO 指标：一组在指标名称中有 "Total"，而另一组没有（例如，"Physical Read Total IO Requests Per Sec" 与 "Physical Read IO Requests Per Sec"）。有谁知道有什么区别？非常感谢。
我使用的Oracle DB：11.2.0.3.0 64bit，两个节点RAC
基于Oracle 12c Database Reference Statistics Descriptions， 不同之处在于 "total" 指标包括系统 activity，如备份和恢复，而另一个指标不包括。
physical read IO requests
Number of read requests for application activity (mainly buffer cache and direct load operation) which read one or more database blocks per request. This is a subset of "physical read total IO requests" statistic.
physical read total IO requests
Number of read requests which read one or more database blocks for all instance activity including application, backup and recovery, and other utilities. The difference between this value and "physical read total multi block requests" gives the total number of single block read requests.