Oracle DB time
Oracle Consulting Tips by Burleson
DB time Oracle
is the amount of elapsed time (in microseconds) spent performing
Database user-level calls. This does not include the time spent on
instance background processes such as PMON.
ADDM’s goal is to improve
the value of a statistic called DB time. DB time is a value that
Oracle calculates to indicate the cumulative time that is spent
processing user requests. ADDM’s goal is to reduce the overall DB
time value, and it does not target individual users or user response
times, and thus the DB time it uses is an aggregate value of overall
system CPU and wait times.
The goal for tuning Oracle process should be to reduce to minimum
CPU time and Wait time so that more transactions can be processed.
This is done by tuning the SQL:
DB Time = CPU time + I/O time +
Non-idle wait time
DB time is total time spent by user
processes either actively working or actively waiting in a database
From this formula we can conclude that database requests are
composed from CPU (service time, performing some work) and wait time
(session is waiting for resources).
Here is a DBV time query from
'Database Time Per Sec';
Here is another query for DB time from
the ASH table:
metric_name = 'Database Time
You can see the current
value of DB time for the entire system by querying the
V$SYS_TIME_MODEL or you can see it for a given session by using the
V$SESS_TIME_MODEL view as seen here:
sample_time between to_date('30032016 10:00:00','ddmmyyyy
sum(value) "DB time"
See also on "db time":
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