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Thursday, February 28, 2008

Good DBA

Today my article is based on general thoughts about Oracle DBA with some technical details.

When we complete oracle certification and start our career as DBA. then we feel very good and happy.

In Oracle Technology we never feel boring. becuase it is very vast we have always new things for learn and we never become 100% expert.

Like Tom Kyte,Jonathan Lewis etc...

Everybody have dream as an Oracle DBA. I have also. want to OCM (Oracle Certified Master) and achieve ACE award from Oracle Corp.

1. What is Oracle DBA ?

DBA is Database Administrator which handle Database. and Oracle is biggest Database software in world right now which we use for maintain company data.

Life of DBA is very challenging.

DBA face new , new issue related to oracle database and try to solve, sometime small issue will take lots of time to sortout.

When we call a person is Complete DBA.

1. A person must be able to handle all database version with two OS platforms

1. Windows 2. Linux/Solaris/Unix

2. A person must be able to handle all backup and recovery related senario.

3. A person must be able to handle & Solve Performance related issues.

Above three are major work which include alots of things.

If you want to be good DBA then you have to always read,read,read oracle related forms,documentation,article etc.

Below are some ORA-ERROR which every DBA face in his/her life.

1. ORA-00600/ORA-07445
Clause: Most likely it is related to bug
Solution: go to metalink and apply patch set.

2. ORA-03113
Clause: It is generic error means lots of reason behind this.
Solution: Depends on condition but best way to search on google/forms.

3. ORA-04031
Clause: Mis-configuration of SGA, insufficient memory
Solution: Sametime need to add memory on system, or sametime need to reduce SGA memory

4. ORA-12154
Clause: Wrong TNS_ENTRY is used.
Solution: Using NETCA tools configure tns entry or check tnsnames.ora file for correct entry.

5. ORA-12368
Clause: It is generic error lots of reason

6. ORA-12500
Clause: It is generic error lots of reason
Solution: increase "processes" parameter, increase physical memory

7. ORA-12528
Clause: It is BUG in 10g (if you face this error in 10g)
Solution: Don't use TNS_ENTRY with connect string or edit listener configuration from STATIC to DYNAMIC.(search on my blog for more)

Below are some question which everyone is confused

1. select count(*) or count(columname) which is faster ?
Answer: Both are same in performance in speed.

2. How frequently index should be rebuild.
Answer: NO, We never need to rebuild index becuase it is not increase database performance

3. For Oracle Database Windows is good OS or Linux is good.
Answer: Linux is much better than Windows for Oracle.

4. How to increase Database Performance?
Answer: Database performance use below methology.

1. Define what database performance is acceptable.
2. When you face performance related problem

Define where is come from means
1. it is related to Instance (SGA Configuration)
2. it is related to Client machine ( SYSTEM configuration)
3. it is related to Network delay

3. check database performance through
1. statspack report, awr report,tk*prof tools,sql trace etc.

Continue with next part...

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