Reg Slow Database

Question

Hi,
Our Database Suddenly become slow in the recent days.
The Same concurrent report which completes in seconds takes hours to complete.
We gone through the awr report and found
Top 5 Timed Events
Event               Waits          Time(s)          Avg Wait(ms)     % Total Call Time     Wait Class
CPU time                         271,488                    38.2     
db file sequential read          1,544,634,048     176,828          0          24.9               User I/O
read by other session          61,394,625     164,873          3          23.2               User I/O
latch: cache buffers chains     1,728,716     62,659          36          8.8               Concurrency
db file scattered read          2,327,370     11,683          5          1.6               User I/O
Your thoughts on it.
Where else in AWR report i have to consider.
Regards
Krishna

Answer 1

When you post a question
- always include a four digit version
- always include platform information
- for this kind of question: the amount of memory in the server
- assuming Unix: vmstat output
- basic spfile parameters
In a normal database it would be very strange db sequential read not to show up in the top 5.
In conjunction with cache buffer chains it seems to indicate you didn't tune sql, and you tried to resolve your performance problems by increasing the SGA.
This never works.
Quoting William Jefferson Clinton, when he defeated George Bush sr: 'It's the application, stupid!'
Right now you did no analysis, and also posted unformatted output, not using the tag.
Much more information is required.
Sybrand Bakker
Senior Oracle DBA