Question regarding using of Explain Plan

Hi. I'm new with Oracle Queries so I have a little obstacles about understanding. I want to learn how to use Explain Plan feature from Oracle
I am using Oracle 9i as back end .
Please tell me how can i use feature of Explain Plan Feature for the below query.
SELECT * FROM emp WHERE empno = 7369
Thanks in advance.

[email protected] wrote:
Hi. I'm new with Oracle Queries so I have a little obstacles about understanding. I want to learn how to use Explain Plan feature from Oracle
I am using Oracle 9i as back end .
Please tell me how can i use feature of Explain Plan Feature for the below query.
SELECT * FROM emp WHERE empno = 7369
Kiran,
Firstly , before anything else, I would suggest to change your handle to anything else and remove the email id from it. Its not good to have the id displayed in any public forum.
About the question, unfortunately, its not that easy to answer. To understand explain plan and how to use it, you need to understand that algorithm/mechanism, whatever you feel like saying, that generates it. Because, explain plan is just the outcome of that mechanism, a final product, its the result of some inputs given by you in the form of your query, predicates, joins and their types and that all bring up the explain plan. Explain plan is basically the constitution of some steps which are used /fixed by optimizer to run the query. I would suggest that you read this page from cover to cover to understand some of the steps and their meanings which are shown to you in the plan. I am giving 10g link as this is a more better version of optimizer than the previous ones and I would suggest you to do experiments on 10g only.
http://download.oracle.com/docs/cd/B19306_01/server.102/b14211/optimops.htm#i21299
And I would suggest that you collect these following books and start reading them. I haven't yet found any thing better than these books.
[Cost Based Oracle Fundamentals (Jonathan Lewis)|http://www.amazon.com/Cost-Based-Oracle-Fundamentals-Experts-Voice/dp/1590596366]
[Troubleshooting Oracle Performance(Christian Antognini )|http://www.amazon.com/Troubleshooting-Oracle-Performance-Christian-Antognini/dp/1590599179/ref=sr_1_1?ie=UTF8&s=books&qid=1240078634&sr=1-1]
[Effectuve Oracle By Design(Tom Kyte)|http://www.amazon.com/Effective-Oracle-Design-Osborne-ORACLE/dp/0072230657/ref=sr_1_1?ie=UTF8&s=books&qid=1240078698&sr=1-1]
It would be real long journey before the mazes of optimizer and explain would be clear so make sure you have patience as well.
HTH
Aman....

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