Oracle Internals from Basic to Advanced....

Dynamic Sampling…._optimizer_dyn_smp_blks

2011-03-27T00:32:00.001+05:30

While working with query Optimizations I came across with Dynamic Sampling and thought to check what it does actually do underneath behind the screens. Today, I have experiment some of the things on the concept and in practical's, so thought of to share across to friends and newly upcoming dba’s. There exists two parameters which controls the sampling behaviour of oracle optimizer when

How Sampling Process Works…of Tanel Poder…..!!

2011-03-11T17:22:00.001+05:30

Expert – Oracle Master Tanel Poder provided number of troubleshooting scripts on his blog. As as per my knowledge most of the Database Administrators and upcoming new comers might have visited the blog and started using the scripts. Even I have checked and tried to understand things how the scripts works. Really in order to understand scripts, it does take time from medium level database

Oracle 11g hints update…

2011-03-06T13:01:00.001+05:30

From Oracle 11g version we have following new hints which are introduced in support for edition based redefinition. CHANGE_DUPKEY_ERROR_INDEX, IGNORE_ROW_ON_DUPKEY_INDEX andRETRY_ON_ROW_CHANGE. I have provided the demo for the above hints and how basically hint works. Perhaps, when we compare across the Performance of usually programming for checking duplicate records prior to insert with

Step by Step Instructions/ Demos…

2011-02-21T14:13:00.001+05:30

I have came across most of the people posting across the demo (or) step by step instructions of physical standby on same system. After looking into the similar questions/posts in forums and not specially to data guard and further regarding the concepts of Oracle and their respective demos. I thought to develop such kind of stuff which would helpful for new DBA’s and on going Database Base

User Schemas..Enterprise Manager..

2011-01-13T01:13:00.001+05:30

Today I have came across one of the question from oracle forum member with respect to user schemas. Question was User created without the schema. Surprized with the issue and tried to replicate the issue. Posting across the results during the replicating the issue. Here we go 1: Microsoft Windows [Version 6.1.7600] 2: Copyright (c) 2009 Microsoft Corporation. All rights reserved

Oracle Optimizer Environment Details–Oracle 11g

2010-12-09T13:12:00.001+05:30

I have seen most of the people who are Developer/DBA, they carry out customization of environment where ever the work. As it would feel better in order to carry out the work. Similarly, while working with oracle performance tuning related activities, it would be initial step to check /find the environment settings of Oracle Optimizer, which provides the information related to the Optimizer

SGA/Granules in Oracle 11g

2010-11-29T11:33:00.001+05:30

Today while going through the oracle 11g Release 2 Documentation, I have came across the content related "Components and Granules in the SGA". I might not have concentrated in earlier on this very much depth and thought that let me dive in the part of ocean for a while and enjoy oracle details and how they are mapped with internals tables and how best we can understand those and we can directly

V$session in 11g

2010-11-12T13:20:00.001+05:30

Each and every person who works on the ORACLE Database, they knows the importance of v$session view. It’s the starting point of troubleshooting of the problems if we consider the systematic approach as Tanel poder says. Yes, let’s today see some things which are “unknown and known” to the DBA’s and they skip some of the details from the v$session view which provides a very valuable and vital in

V$OPEN_CURSOR and ORA-01000: maximum open cursors exceeded

2010-11-08T11:57:00.001+05:30

Let’s today talk about the ORA-01000, during past week application developers are facing the above issue with cursors, during their development, as their clients got stuck. They just pinged me ad updated the same and I had checked it was one of common issue where now-a-days application developers are facing across due to the improper coding while dealing with cursors. I had checked statistics

V$SGA and V$SGASTAT kernel details and Numa Pool in Oracle 11g Release 2.

2010-10-20T01:31:00.001+05:30

I was doing an R&D in ORACLE 11g Release 2 and thought of to check how the data is getting populated across the views. As every other DBA knows how important is the above v$ views and what type of information does it provide. I am not going talk about the same old story regarding the purpose and usage of the above v$ views, as I believe you can get enough information from the ORACLE

Cold Backup–DB Quiesce State…

2010-10-15T18:36:00.001+05:30

Oracle Documentation says Note: You cannot perform a cold backup when the database is in the quiesced state, because Oracle Database background processes may still perform updates for internal purposes even while the database is quiesced. In addition, the file headers of online datafiles continue to appear to be accessible. They do not look the same as if a clean shutdown had been performed.

Does the V$BLOCKING_QUIESCE provide efficient information..

2010-10-15T18:12:00.001+05:30

I had started my journey to dig up the each bit by bit and concept wise of Oracle Documentation of 11g Release 2, While going through the oracle documentation I came across regarding the database quiesce state,as every other DBA knows the important aspect of this command reference. Let me put up some important aspects which I came across today, might be others are well known with these things,

Oracle Enterprise Linux Installation on Oracle Virtual Box

2010-10-15T12:52:00.001+05:30

I was intended to post the video tutorials long back before, but could not able to do so due some busy schedule and commitments which came on fly. Finally at any cost started with demo of Oracle Enterprise Linux OS installation. Please find the video tutorial which is converted in flash version and can be able to view internet explorer. Feel free to post across the valuable inputs/comments, as

Oracle Database Properties and Time Zones…

2010-10-07T17:03:00.001+05:30

Let us today go through the details about the Database properties time zones as they act (or) take part important role in the life of Oracle Database. Let’s see what the information we get from the above concepts and what best we can make use of information. During the installation of Oracle usually we specify the default tablespace type, so Oracle Database assigns to this tablespace any

Internals of v$instance view….

2010-10-04T00:16:00.001+05:30

Every Database Administrator is having an idea from where to get the details about the instance, i.e., v$instance. But today let us see from where these details comes from and what are the other details and important information with respect to our instance. let’s see how much they are useful with our understanding of ORACLE Architecture and troubleshooting aspects. Let’s query the view and

Does User INTERNAL exists in Oracle 11g Release 2.

2010-10-03T22:18:00.001+05:30

Before going forward to the User and access privileges and actual subject which was quoted above, I will talk about the Orapwd initially for a while. Every Database Administrator knows what is the use of orapwd utility. I am not going put forward any thing repeatable but, let us look some new things about the information is transferred and from where we are getting … Let’s see syntax and some

ORACLE User Accounts and Authentication…

2010-10-03T16:06:00.001+05:30

Two administrative user accounts are automatically created when Oracle Database is installed: SYS (default password: CHANGE_ON_INSTALL) SYSTEM (default password: MANAGER) SYS When you create an Oracle database, the user SYS is automatically created and granted the DBA role. SYSTEM When you create an Oracle Database, the user SYSTEM is also automatically created and granted the DBA role.

Finding the Oracle Software Version…

2010-10-03T15:01:00.001+05:30

It’s very much important to check for Oracle Software Version and its details. During the part of troubleshooting or applying patches we need to know the importance of the version numbers and what it signifies. 1: SQL> desc PRODUCT_COMPONENT_VERSION 2: Name Null? Type 3: ----------------------------------------- -------- --

Connecting to the Database with SQL*Plus

2010-10-03T14:32:00.001+05:30

I have seen some many posts in forums regarding the connecting to oracle database from client. Let us talk about the basics – how to connect to Oracle Database from beginner point of view. Before connecting to Oracle DB there exist some pre-requisite need to be carry out based on the environments you deal with. If you are working on Linux or Unix environment then follow the below environment

Red Hat Certified Engineer - Red Hat Enterprise Linux 5

2010-10-03T11:31:00.001+05:30

Recently, I had completed my Red hat certification which was very much interesting and very much excited after getting results after 24 hours. As similar to ORACLE, I though we should have similar experience in troubleshooting the issues from Operating system perspective which enhance our selves in resolving issues or else at least help us to find the real issue where it persists. Coming to

db_file_multiblock_read_count not in effect…

2010-10-02T19:20:00.001+05:30

With reference to one of the question in forum about couple of days where it was asked regarding the Hash join index is favoured or Nested loops. The part of the story deals with big and small tables of size 550 MB and 26 GB. You can go through the below link for your reference. http://forums.oracle.com/forums/thread.jspa?threadID=1319851&tstart=0&start=15 Charles Hooper had provided very

Does Import Works if existing structure of segment is slightly Modified….!!

2010-08-10T01:10:00.001+05:30

I have came across with one of the issue in production where one of my colleague tried to carried out export and import of one particular table. Perhaps he had modified the structure of table slight by adding new columns to existing table. As per my understanding if you carry out the export either conventional or direct – Oracle holds the metadata information along with actual data (if you

What are Editions in Oracle 11g R2..!!

2010-08-08T23:32:00.001+05:30

Today, I will talk about the one of the new features of oracle 11g Release 2 “Editions in Oracle”. This is one the very helpful feature which oracle introduced and made my Job very much easier in day to day life as we upgrade product /applications over a period of time..! If you consider product based companies, usually from developer perspective as I came across, we need to update the

Oracle 11gR2 on windows 7…

2010-08-08T19:45:00.001+05:30

Hi all, It’s been a long time since, I have not updated the blog post, due to some hectic schedules etc., Now got some time to spend on my blog and will try to make sure that I will post across my experience from today onwards which I face across in my daily routine… Finally, ORACLE provided the 11g release for windows and I had set up successfully with out any installation issues on my

DBMS Change Notification

2009-09-07T01:28:00.001+05:30

Hi All, Recently about a week ago I have seen the queries regarding the DBMS change notification. We use the package properly it’s going to be an alternative for ORACLE auditing. Since, its going to track the DML or DDL changes on the objects associated with the queries. Looking into that I have provided a demo for that. Here goes [pavan@cvrsnicavir13 ~]$ sqlplus / as sysdba SQL*Plus