Tuning Goldilocks SQL

... then Goldilocks went into the bears' Data Centre and there were 3 Oracle databases. The first was a Data Warehouse. Goldilocks checked the AWR, but all the SQLs were to-o-o-o-o-o-o-o big; they all used full scans, hash joins, bitmap-index combining, partition pruning and parallelism and couldn't be tuned any more. So Goldilocks went to the second Oracle database. It was an OLTP system with hundreds of concurrent users. Goldilocks fired up SQL Tuning Advisor, but all the SQLs were to-o-o-o-o-o-o-o small; they used unique index scans and cluster-joins and couldn't be tuned any more. So Goldilocks went to the third Oracle database. It was an Operational Data Store with a rolling 3 month retention. Goldilocks found SQLs that were joining a million rows with Nested Loops joins, buffer cache hit ratios of 50%, and under-utilised disk. She smiled, opened up Tom Kyte's Expert Oracle eBook on her second monitor and got to work. This database was ju-u-u-u-u-u-u-u-st right ...

It is seen that Windowsx64 Edition Operating System has following two directories:-
1. Program Files
2. Program Files(x86)
Windows XP Professional x64 Edition redirects the \Program Files directory for all programs that are 32-bit during the installation to the \Program Files(x86) directory. Programs that are 64-bit compatible are installed into the \Program Files directory.
The \Windows\SysWOW64 directory is where 32-bit system files are installed.

During my experiences with different environments, I have been tasked with maintaining passwords for different information systems. This includes operating system accounts (root, oracle, administrator) and Database accounts (sys, system, dbsnmp).

It can be sometimes difficult to remember many different passwords. I have seen some people overcome this by documenting the passwords, sometimes just in a plaintext file, sometimes encrypted, sometimes just on a ‘Post-It’ Note under the keyboard.

I try and retain the passwords in memory.

Part of my job is teaching for Oracle University, and I'm often asked about OCP exam technique. Here are a few hints. The OCM exam is very different, and the confidentiality rules forbid me from discussing it, so please don't ask.

Everyday most of us deal with multiple string functions in Sql. May it be for truncating a string, searching for a substring or locating the presence of special characters.

The regexp functions available in Oracle 10g can help us achieve the above tasks in a simpler and faster way.

Working with LDAP has made me appreciate the maturity of the Oracle RDBMS. That said, LDAP is pretty popular it seems. To that end my cohort in crime Dave Smith and I (Kevin Meade) have been tasked with many a work request to update LDAP entries related to database data. In integrating our databases and LDAP via the DBMS_LDAP package we came across this error. A quick Internet search revealed lots of people with the same error but no answers. It turns out that the error is exactly what it says it is, but that finding the reason for it is another matter. Here we discuss what we think the error means and the three most likely ways to get it.

Today I planned to test “Recover the datafile without prior backup”

Currently there is no failure in database. I shutdown the database & removed the below datafile in OS level “D:\ORACLE\APP\ORADATA\CHE\TEST.DBF”.

Note:

1.Database must be in archive log mode.
2.We need all the archive log files from lost datafile created.

1.Login into che database

C:\>set oracle_sid=CHE

SQL*Plus: Release 11.1.0.7.0 - Production on Wed May 19 14:21:03 2010

Copyright (c) 1982, 2008, Oracle.

What is Recycle Bin
Oracle has introduced "Recycle Bin" Feature Oracle 10g to store all the dropped objects.
If any table in Oracle 10g is dropped then any associated objects to this table such as indexes,
constraints and other dependant objects are simply renamed with a prefix of BIN$$.

Why Recycle Bin
A user drops a very important table--accidentally, of course--and it needs to be revived as soon as possible.

Oracle Data Recovery Advisor 11g new feature

Data recovery advisor is one of the oracle 11g new features.

The Data Recovery Advisor tool can assist with diagnosing media failures, making recommendations and providing the RMAN commands to resolve the problem.

Data Recovery advisor we have used three commands.

1.List failure
2.Advice failure
3.Repair failure

How it works?

1.List failure:

The Data Recovery Advisor stores its information outside the database in the Automatic Diagnostic Repository (ADR - V$diag_info)

If you find any problem in database and Data recovery a

Sometime is necessary to move all database objects from one tablespace to another.

Basically are tables, indexes and lobs.

This script permit move database objects from one user and/or tablespace to another:

[code]
set echo off
set heading off

var tbs_source varchar2;
var tbs_dest varchar2;
var schema_user varchar2;

-- '' if it isn't relevant.
exec :tbs_source := 'SOURCE_TBS';
-- '' if it isn't relevant.
exec :schema_user := 'SOURCE_USER';
exec :tbs_dest := 'DEST_TBS';

select 'Transporting tablespace ' || :tbs_source || ' or user ' || :schema_user || ' to tables