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Oracle AWR
Hi Team,
when we investigate the I/O issues of the AWR report, the "Top 10 Foreground Events by Total Wait Time" showed below.
Which factors related to the IO performance we should focus on and what they means? thanks.
Event Waits Total Wait Time (sec) Wait Avg(ms) % DB time Wait Class
DB CPU 344.7 46.3
local write wait 54,114 193.8 26.0 User I/O
db file sequential read 126,267 56.2 0 7.6 User I/O
zhaos2
643 Posts
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April 21st, 2017 20:00
The 'db file sequential read' is disk I/O related. The 'Wait Avg' > 20ms is unacceptable, obviously it is not an issue in your case.
If the 'db file sequential read' caused large waiting time (>20ms) you can find more detail information about the blocks accessed in V$session_wait, V$session_event, and dba_extents.
DB file sequential read (%)