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Archive for the ‘Basics’ Category


What’s new with Oracle 12C Release 2: RMAN Recovery Options

Posted by FatDBA on March 24, 2017

Hi Everyone,

Oracle introduced the long awaited Database 12c Release 2 earlier this year at Oracle Open World. The latest major release since 2013, originally announced in beta at Oracle Open World 2015, may have left some customers scratching their head after hearing the latest release would be what Oracle is calling “Cloud first availability”.

Some of the key Oracle Database 12c Release 2 highlights are:
Multitenancy improvements, which allow for more databases to run on a single machine, 4,096 to be exact, up from 252 in 12.1.
Performance increases with SQL Performance Analyzer, DB Replay and SQL Plan Management. Users can now increase query execution with the Optimizer Statistics Advisor, SQL JOIN processing.
Availability enhanced features in RMAN like table recovery, transport data across platforms, enhancements related to online operations and ongoing enhancements with Oracle Data Pump, SQL*Loader and external tables.

One of the coolest feature i have noticed during recent tests of Oracle 12c R2 was related with the RMAN recovery.
With this newest offering from Oracle Corporation now you can “RECOVER DATABASE UNTIL AVAILABLE REDO” 🙂

Hope That Helps
Prashant Dixit

Posted in Basics | Leave a Comment »

Part 1: ASM Installation on 11gR2 (VMWare)

Posted by FatDBA on January 10, 2016

Hello Everyone,
Today i would like to start series/chapters describing Oracle Automatic Storage Management (Oracle ASM) concepts and provides an overview of Oracle ASM features. Followed posts will covers subjects like Installation, Configuration, Administration/Management, Monitoring. Troubleshooting and Optimization etc.

In this maiden post (Part 1) i would like to discuss and elaborate about ASM installation and related areas.

Considering that you already have the OS ready with all packages per-installed before we begin our ASM installation on the top. I will start with right from the scratch.

Step 1:
Preparing Disks or Partitions which will be used while creating the ASM diskgroups.
I’ve created 3 Persistent Disks each of 4GB in size from the VM Disk (I will perform all steps in VM environment).

This is how the VM Setting will look like once you are done with the Disk creation.
*Forgot about the Fifth Hard Disk of 10GB for now. Will explain the usage later on the series.


Once you have the disks created, Next you’ll have to format the newly created disks to make them usable: Using fdisk command. Command displays the status of available newly created partitions/disks as:
/dev/sdb, /dev/sdc, /dev/sdd – Each of 4GB (4294 MBs) in size.

[root@localhost ~]# fdisk -l

Disk /dev/sda: 91.3 GB, 91268055040 bytes, 178257920 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000aab6c

Device Boot Start End Blocks Id System
/dev/sda1 * 2048 1026047 512000 83 Linux
/dev/sda2 1026048 178257919 88615936 8e Linux LVM

Disk /dev/sdb: 4294 MB, 4294967296 bytes, 8388608 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

Click Here to Read More!!

Posted in Advanced, Basics | Tagged: | Leave a Comment »

runInstaller Error: An unexpected error has been detected by HotSpot Virtual Machine

Posted by FatDBA on January 6, 2016

Hello Everyone,
Installing your Oracle Software using GUI Method requires to call “runInstaller” script and is always an easy step if you have proper permissions, DISPLAY settings in place.
But here i would like to discuss one of the case where I’ve spent several hours to fix one of the error that occurred every-time i called runInstaller script even after setting all required permissions and DISPLAY variables.

It fails to render the installer and creates a log file under /tmp directory with below mentioned contents.

# An unexpected error has been detected by HotSpot Virtual Machine:
# SIGSEGV (0xb) at pc=0x0000003e2ce14d70, pid=4000, tid=140717162321680
# Java VM: Java HotSpot(TM) 64-Bit Server VM (1.5.0_51-b10 mixed mode)
# Problematic frame:
# C [ld-linux-x86-64.so.2+0x14d70]

————— T H R E A D —————

Current thread (0x000000004220d3f0): JavaThread “AWT-EventQueue-0” [_thread_in_native, id=4014]

siginfo:si_signo=11, si_errno=0, si_code=128, si_addr=0x0000000000000000

RAX=0x0000000000000001, RBX=0x000000004216ae50, RCX=0x000000009eba2203, RDX=0x000000000fabfbff
RSP=0x00007ffb44792278, RBP=0x00007ffb447923c0, RSI=0x0000000000000000, RDI=0x0000000000000058
R8 =0x0000000000000000, R9 =0x0000000000000000, R10=0x00007ffb447921f0, R11=0x000000004216ae50
R12=0x00007ffb447923e8, R13=0x0000000041f85330, R14=0x0000000000000000, R15=0x0000000000000000
RIP=0x0000003e2ce14d70, EFL=0x0000000000010202, CSGSFS=0x0000000000000033, ERR=0x0000000000000000

Top of Stack: (sp=0x00007ffb44792278)
0x00007ffb44792278: 0000003e2ce0aaea 0000000000000000

Signal Handlers:
SIGSEGV: [libjvm.so+0x67ed60], sa_mask[0]=0x7ffbfeff, sa_flags=0x14000004
SIGBUS: [libjvm.so+0x67ed60], sa_mask[0]=0x7ffbfeff, sa_flags=0x14000004
SIGFPE: [libjvm.so+0x582020], sa_mask[0]=0x7ffbfeff, sa_flags=0x14000004
SIGPIPE: [libjvm.so+0x582020], sa_mask[0]=0x7ffbfeff, sa_flags=0x14000004
SIGILL: [libjvm.so+0x582020], sa_mask[0]=0x7ffbfeff, sa_flags=0x14000004
SIGUSR1: SIG_DFL, sa_mask[0]=0x00000000, sa_flags=0x00000000
SIGUSR2: [libjvm.so+0x583ed0], sa_mask[0]=0x00000000, sa_flags=0x14000004
SIGHUP: [libjvm.so+0x5839a0], sa_mask[0]=0x7ffbfeff, sa_flags=0x14000004
SIGINT: [libjvm.so+0x5839a0], sa_mask[0]=0x7ffbfeff, sa_flags=0x14000004
SIGQUIT: [libjvm.so+0x5839a0], sa_mask[0]=0x7ffbfeff, sa_flags=0x14000004
SIGTERM: [libjvm.so+0x5839a0], sa_mask[0]=0x7ffbfeff, sa_flags=0x14000004

————— S Y S T E M —————

OS:Red Hat Enterprise Linux Server release 6.0 (Santiago)

uname:Linux 2.6.32-573.12.1.el6.x86_64 #1 SMP Tue Dec 15 06:42:08 PST 2015 x86_64
libc:glibc 2.12 NPTL 2.12
rlimit: STACK 10240k, CORE 0k, NPROC 16384, NOFILE 65536, AS infinity
load average:0.09 0.06 0.08

CPU:total 1 em64t

Memory: 4k page, physical 2046684k(69828k free), swap 2031612k(2031612k free)

vm_info: Java HotSpot(TM) 64-Bit Server VM (1.5.0_51-b10) for linux-amd64, built on Jun 6 2013 09:59:46 by java_re with gcc 3.2.2 (SuSE Linux)

time: Sat Jan 2 23:09:21 2016
elapsed time: 2 seconds

The workaround to the problem is to set “LD_BIND_NOW” environment variable to a value “1” as shown below and re-launch the installer.

bash-4.1$ export LD_BIND_NOW=1
bash-4.1$ ./runInstaller
Starting Oracle Universal Installer…

Checking Temp space: must be greater than 120 MB. Actual 27339 MB Passed
Checking swap space: must be greater than 150 MB. Actual 4031 MB Passed
Checking monitor: must be configured to display at least 256 colors. Actual 16777216 Passed
Preparing to launch Oracle Universal Installer from /tmp/OraInstall2013-07-01_03-29-40AM. Please wait …

This bug seems to have reported on &

Hope That Helps
Prashant Dixit

Posted in Advanced, Basics | Tagged: , | 1 Comment »

Using DBCA (DB Create) in Silent Mode.

Posted by FatDBA on August 23, 2013

DBCA is one of the most important and easiest utility to create new databases. Most of us have used it during our careers in GUI mode, but we have an option to launch it in non-graphical mode (Non-Interactive Mode) as well. Below provided steps can be performed to create database in silent/non-interactive mode. So you can launch DBCA in text mode from your favorite ssh client/terminal like putty, secureCRT, SSH Tectia Client etc. and can save yourself from that ‘old’ manual DB create methods (Using catprocs, catalog sql’s and creating new dump directories).

To create database: This requires a response file which includes all necessary details like GGDBNAME (Global Database Name), SID, Listener Name, SYS/SYSTEM/DBSNMP/SYSMAN Passwords etc.
Browser the response file (ORACLE_HOME/assistants/dbca) and make all mandatory changes.

Step 1: Location of response file
[oracle@prashant dbca]$ pwd
/u01/app/oracle/product/11.2.0/db_1/assistants/dbca    — Default Location of Response File.

[oracle@prashant dbca]$ ls
dbca.rsp  doc  jlib  logs  templates

Create a copy of original file.
[oracle@prashant dbca]$ cp dbca.rsp  dbcacreatedb.rsp

[oracle@prashant dbca]$ ls
dbcacreatedb.rsp  dbca.rsp  doc  jlib  logs  templates

Step 2:
Edit all mandatory changes in response file.
GDBNAME = “silent”
SID = “silent”
SYSPASSWORD = “oracle90”

Although there are various sections inside the response file “.rsp” file like createdatabase, deleteDatabase, createTemplateFromDB or createCloneTemplate. In this post we have talk only about ‘createDatabase‘ and is the area of interest (Used to create new database).

All Examples :
1. dbca -progress_only -responseFile <response file>
Display a progress bar depicting progress of database creation

2. dbca -silent -responseFile <response file>
Creates database silently. No user interface is displayed.

3. dbca -silent -createDatabase -cloneTemplate
-responseFile <response file>    
Creates database silently with clone template. The template in
responsefile is a clone template.

4. dbca -silent -deleteDatabase -responseFile <response file>
Deletes database silently.

Step: 3

So, we are going to install the database using ‘STEP 3’ without using -cloneTemplate. This will create database silently and will show progress in percentages.
[oracle@prashant dbca]$ dbca -silent -createDatabase -responseFile dbcacreatedb.rsp
Copying database files
1% complete
3% complete
11% complete
18% complete
26% complete
37% complete
Creating and starting Oracle instance
40% complete
45% complete
50% complete
55% complete
56% complete
60% complete
62% complete
Completing Database Creation
66% complete
70% complete
73% complete
85% complete
96% complete
100% complete
Look at the log file “/u01/app/oracle/cfgtoollogs/dbca/silent/silent.log” for further details.

It seems that Database Creation is successful completed. Let’s check creation  log file.
File: “/u01/app/oracle/cfgtoollogs/dbca/silent/silent.log”

Okay, while checking log file i found some new entries after creating database:

Database creation complete. For details check the log-files at:
Database Information:
Global Database Name:silent
System Identifier(SID):silent

[oracle@prashant dbca]$ cd /u01/app/oracle/cfgtoollogs/dbca/silent
[oracle@prashant silent]$ ls -ltr
total 104
-rw-r—– 1 oracle oinstall  1372 Aug 23 11:47 rmanRestoreDatafiles.sql
-rw-r—– 1 oracle oinstall   330 Aug 23 11:49 CloneRmanRestore.log
-rw-r—– 1 oracle oinstall  1135 Aug 23 11:50 cloneDBCreation.log
-rw-r—– 1 oracle oinstall     8 Aug 23 11:50 postScripts.log
-rw-r—– 1 oracle oinstall     6 Aug 23 11:50 lockAccount.log
-rw-r—– 1 oracle oinstall   349 Aug 23 11:51 postDBCreation.log
-rw-r—– 1 oracle oinstall   458 Aug 23 11:51 OraDb11g_home1_silent_creation_checkpoint.xml
-rw-r—– 1 oracle oinstall 66392 Aug 23 11:51 trace.log
-rw-r—– 1 oracle oinstall   654 Aug 23 11:51 silent.log

* There are some interesting files generated during DB creation like CloneRmanRestore.log, cloneDBCreation.log, postDBCreation.log and rmanRestoreDatafiles.sql.

Let’s check our new database ‘Silent’.
[oracle@prashant silent]$ ps -ef|grep pmon
oracle   12671     1  0 Aug20 ?        00:00:03 ora_pmon_sairam
oracle   20771     1  0 11:50 ?        00:00:00 ora_pmon_silent
oracle   22315 18308  0 13:06 pts/2    00:00:00 grep pmon

Okay we have a PMON for databse (Silent).
[oracle@prashant silent]$ . oraenv
ORACLE_SID = [sairam] ? silent
The Oracle base for ORACLE_HOME=/u01/app/oracle/product/11.2.0/db_1 is /u01/app/oracle
[oracle@prashant silent]$ sqlplus / as sysdba

SQL*Plus: Release Production on Fri Aug 23 13:07:04 2013
Copyright (c) 1982, 2009, Oracle.  All rights reserved.

Connected to:
Oracle Database 11g Enterprise Edition Release – Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL> select name, open_mode from v$database;

——— ——————–


Prashant Dixit
“Sharing is Good”

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Oracle 12c ( is officially released.

Posted by FatDBA on June 26, 2013




Finally the long wait is over, 12c ( has released and is available on Oracle official website to download and test.

Link: http://www.oracle.com/technetwork/database/enterprise-edition/downloads/index.html

Posted in Basics | Tagged: | Leave a Comment » (Why so many 1’s, 2’s, 3’s and 4’s)

Posted by FatDBA on May 16, 2013


Why we have so many numbers (1,2,3,4) in ?. Alright, today I’ll try to explain significance of these numbers and it’s relevance.

11.X .X. X.X
Major Database Release Number:
Major database release number, major new edition, contains significant new functionality. It represents a major new version of the software that contains significant new functionality.

X. 2. X. X
Database Maintenance Release Number:
Number increases when bug fixes or new features to existing programs become available.

X . X .O. X .X
Middleware Release Number:
Release level of Oracle Middleware. In case of 10g/9i it was Oracle Application Server Release Number.

X. X . X. 3. X
Component-Specific/Patch Release Number:
A Patch release contains fixes for serious bugs that cannot wait until the next maintenance releasefor example, component patch sets or interim releases.

X. X . X. X. 4
Platform-Specific Release Number:
Usually this is a patch set Updates.
Used to identify a particular emergency patch release of a software product on that operating system, it usually fixes or works around a particular, critical problem

SQL> select banner from v$version;

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Me explaining PGA & UGA.

Posted by FatDBA on April 27, 2013

• Program global area (PGA)

PGA is memory specific to operating process that is not shared by other processes in the system. Because PGA is process specific, it is never allocated in the SGA. Access to the PGA is exclusive to the server process.

An analogy for a PGA is a temporary countertop workspace used by a file clerk. In this analogy, the file clerk is the server process doing work on behalf of the customer (client process). The clerk clears a section of the countertop, uses the workspace to store details about the customer request and to sort the folders requested by the customer, and then gives up the space when the work is done.


Not all of the PGA areas will exist in every case. PGA is subdivided into different areas.

– Session Memory: Also known as Stack Space (Session Memory).

– Private SQL Area:
This area holds information about a parsed SQL statement and other session specific information for processing for processing. When a server process executes SQL or PL/SQL code, the process uses the private SQL area to store bind variable values, query execution state information, and query execution work areas.

Private SQL Area is subdivided in to following parts:
Run-Time Area: This area contains query execution state information. For example, the run-time area tracks the number of rows retrieved so far in a full table scan.
Persistent Area: Area contains bind variable values.
– SQL Work Areas:
This area is a combination of Sort Area, Hash Area and Bitmap Merge Area. A sort operator uses the sort area to sort a set of rows. Similarly, a hash join operator uses a hash area to build a hash table from its left input, whereas a bitmap merge uses the bitmap merge area to merge data retrieved from scans of multiple bitmap indexes.
WORKAREA_SIZE_POLICY (AUTO | MANUAL) specifies the policy for sizing work areas. When set to Auto, Work areas used by memory-intensive operators (such as sort, group-by, hash-join, bitmap merge, &  bitmap create) are sized automatically.

PGA_AGGREGATE_TARGET specifies the target aggregate PGA memory available to all server processes attached to the instance.

Setting PGA_AGGREGATE_TARGET to a nonzero value has the effect of automatically setting the WORKAREA_SIZE_POLICY parameter to AUTO. This means that SQL working areas used by memory-intensive SQL operators (such as sort, group-by, hash-join, bitmap merge, and bitmap create) will be automatically sized. A nonzero value for this parameter is the default since, unless you specify otherwise, Oracle sets it to 20% of the SGA or 10 MB, whichever is greater.

Setting PGA_AGGREGATE_TARGET to 0 automatically sets the WORKAREA_SIZE_POLICY parameter to MANUAL. This means that SQL workareas are sized using the *_AREA_SIZE parameters.
In below image, a pointer (Cursor) pointing towards ‘Private SQL Area’ to fetch information. The client process is responsible for managing private SQL areas.


* NOTE: For dedicated sessions, the UGA is a part of the RAM heap in the PGA that controls user sessions space for sorting and hash joins.  If you are forced to use shared servers (the Multi-threaded Server or MTS) the UGA is inside the SGA large_pool_size region).
In sum, when using a dedicated connection, the User Global Area (UGA) supplements the PGA with additional memory for the user’s session, such as private SQL areas and other session-specific information such as sorting and session message queues.



• UGA (User Global Area)
The UGA is session memory, which is memory allocated for session variables, such as logon information, and other information required by a database session. Essentially, the UGA stores the session state.

The UGA must be available to a database session for the life of the session. For this reason, the UGA cannot be stored in the PGA when using a shared server connection because the PGA is specific to a single process. Therefore, the UGA is stored in the SGA when using shared server connections, enabling any shared server process access to it. When using a dedicated server connection, the UGA is stored in the PGA.


UGA has following sections:
Session Variables
OLAP Pool – This sessions opens automatically whenever a user queries a dimensional object like CUBE.


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Enterprise Cloud Infrastructure for Dummies (Oracle Special Edition – PDF Format) E-Book

Posted by FatDBA on February 19, 2013

Get your own copy of Enterprise Cloud Infrastructure for Dummies, Oracle Special Edition.
Source: Oracle.com

Link: http://www.oracle.com/webapps/dialogue/ns/dlgwelcome.jsp?p_ext=Y&p_dlg_id=11847803&src=7618000&Act=8


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Authentication: Password File and OS Based in Oracle.

Posted by FatDBA on December 28, 2012

Diffrence between “/ as sysdba” and “sys/pswrd as sysdba”

— sqlplus “/as sysdba” it mean is you use OS authorization and your user must member of dba(ORA_DBA) OS group,else operation will fail.
— sqlplus sys/pass@sid as sysdba it mean is you use passwordfile authorization .And in this case you need properly configure this file also need set remote_login_passwordfile= EXCLUSIVE or SHARED.

And @sid (sqlplus sys/pass@sid as sysdba) also need listener to be up, can be done either in the server or client side based on the entry in your tnsnames.ora otherwise you’ll receive error message on the SQL terminal the moment you try logging – ORA-12541: TNS:no listener
sqlplus / as sysdba does not require listener to be up but has to be done in the server side.

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LMT vs DMT Tablespaces.

Posted by FatDBA on December 26, 2012

When Oracle allocates space to a segment (like a table or index), a group of contiguous free blocks, called an extent, is added to the segment. Metadata regarding extent allocation and unallocated extents are either stored in the data dictionary, or in the tablespace itself. Tablespaces that record extent allocation in the dictionary, are called dictionary managed tablespaces, and tablespaces that record extent allocation in the tablespace header, are called locally managed tablespaces.

SQL> select tablespace_name, extent_management, allocation_type from dba_tablespaces;

—————————— ———- ———
SYSTEM                         DICTIONARY USER
SYS_UNDOTS                     LOCAL      SYSTEM
TEMP                           LOCAL      UNIFORM

Oracle use the data dictionary (tables in the SYS schema) to track allocated and free extents for tablespaces that is in “dictionary managed” mode. Free space is recorded in the SYS.FET$ table, and used space in the SYS.UET$ table.

SQL> CREATE TABLESPACE etr1 DATAFILE ‘/oradata/etr1_01.dbf’ SIZE 80M
Using LMT, each tablespace manages it’s own free and used space within a bitmap structure stored in one of the tablespace’s data files.

SQL> CREATE TABLESPACE etr2 DATAFILE ‘/oradata/etr2_01.dbf’ SIZE 80M


Advantages in using Locally Managed Tablespaces Over Dictionary Managed Tablespaces

  • Because locally managed tablespaces do not record free space in data dictionary, it reduces contention on these tables.
  • Local management of extents automatically tracks adjacent free space, eliminating the need to coalesce free extents.
  • Sizes of extents that are managed locally can be determined automatically by the system. Alternatively, all extents can have the same size in a locally managed tablespace.
  • Reduced fragmentation

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