Top wait events in awr

Question

hi,
We are using 11.2.0.3.0 on solaris 10 facing slow performance, following are the Wait Events in AWR report, need assistance to overcome it. Also if any specific document to analyze AWR report and to pin point the performance bottleneck.
Foreground Wait Events
Avg
%Time Total Wait
wait
Waits   % DB
Event                        
Waits -outs   Time (s)
(ms)
/txn   time
direct path read           
308,729
0
21,191 
69
58.0   39.5
db file sequential read    
208,754
0 
3,742 
18
39.2
7.0
cursor: pin S           
19,541,899
0 
2,561  
0  3,668.5
4.8
Background Wait Events
Avg
%Time Total Wait
wait
Waits   % bg
Event                        
Waits -outs   Time (s)
(ms)
/txn   time
log file parallel write     
26,479
0   
942 
36 
5.0   40.3
db file parallel write     
216,823
0   
809  
4
40.7   34.6
control file sequential re  
11,673
0    
56  
5 
2.2
2.4
control file parallel writ   
6,280
0    
35  
6 
1.2
1.5
direct path read               
534
0    
26 
49 
0.1
1.1

Answer 1

You need to identify if you are excessively running Parallel Query -- too many queries being parallelised and doing direct path reads bypassing the buffer cache.
In 11gR2, you might also find full table scans of large tables becoming direct path reads.
See this thread :  https://forums.oracle.com/thread/2552571
Hemant K Chitale