System Events by Percent

The System Events by Percent report shows the major events in the database and their contribution to overall response time.   For a complete description of the v$ views, get the "free 11g poster" sponsored by Quest Software. 

Hidden system events

With each new release of Oracle, system events and system statistics are changed. For example, here is a query to show changed system statistics for the database writer process between Oracle8i and Oracle9i:

sql> select distinct name from v$sysstat where name like 'DBWR%'


NAME
----------------------------------------------------------------
DBWR Flush object call found no dirty buffers
DBWR Flush object cross instance calls
DBWR buffers scanned
DBWR checkpoint buffers written
DBWR checkpoint write requests
DBWR checkpoints
DBWR cross instance writes
DBWR free buffers found
DBWR incr. ckpt. write requests
DBWR lru scans
DBWR make free requests
DBWR revisited being-written buffer
DBWR skip hot writes
DBWR summed scan depth
DBWR timeouts
DBWR transaction table writes
DBWR undo block writes

We van use the v $event_name view to quickly locate all new system events in Oracle9i. Here is a quick query to locate new views:

select
name
from
v$event_name@oracle9i
minus
select
name
from
v$event_name@oracle8i
;

Oracle event wait analysis is an extremely sophisticated part of Oracle system tuning. In order to be effective, an Oracle wait analysis must interrogate v$system_event to look at system events that are currently happening within your system. Excessive waits on system events can indicate disk I/O bottlenecks, network bottlenecks, or additional external environmental problems that are causing slowdowns within your Oracle database.