Quesry taking more time to execute

Question

Dear All,
User complained that his query is taking more time than yesterday and DB performance is also very slow, so what would be your strategy to check and fix the problem.
What could be the right approach to check and fix this.
Regards,
DevD!
Edited by: user12138514 on Nov 8, 2009 9:35 PM

Answer 1

And here is the cause list for slow performance:
Slow Network connection.
Bad Connection management.
Bad Use of Cursors and the Shared Pool
Bad SQL or Query is not perfectly tune or not using bind variables.
Use of nonstandard initialization parameters.
Getting Database I/O Wrong
Redo Log Setup Problems
Serialization of data blocks in the buffer cache due to lack of free lists, free list groups, transaction slots (INITRANS), or shortage of rollback segments.
Long Full Table Scans.
High Amounts of Recursive (SYS) SQL
Deployment and Migration Errors
Table require analyzed.
Table require indexed.
Overparsing.
You have old discs.
Not enough memory.
SGA is too small or too big.
Same for cache buffer.
Your OS need tuning.
Your disc is full.
Running so many instances on a single server.
You applications are badly written.
Your applications were ported from Sybase or Microsoft SQL Server.
Your applications were ported from DB2.
Your applications dynamically create temp tables.
Someone wrote referential integrity using triggers, java, vb ...
Someone wrote replication using triggers, java, vb ...
Someone wrote a sequence using max + 1.
Table datatypes are not as per DBMS concepts; like Dates and numbers are stored as strings.
The statistics are not up to date.
There are no statistics.
What are statistics?
We are using RBO.
That's a few of the possible causes I could think of, there are lots of others.
-To analyze your application, you can install Statspack. It will give you some indications.
Hth
Girish Sharma