About Ravi Karamsetty

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So far Ravi Karamsetty has created 69 blog entries.

No package mysql-server available

Starting CentOS7 MySQL is replaced with MariaDB. You might encounter the following error “mysql -u root -p4Samsung4” when you try installing mysql using yum.


[root@myhost~]# yum install mysql-server
Loaded [...]

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centos7 – mysql install fails due to conflict in libmysqlclient.so

We recently built new linux server using CentOS Version 7.0. This release of CentOS comes with MariaDB and MySQL is not a standard offering.

When I tried […]

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Oracle Goldengate – unable to start integrated replicat – OGG-00446

For one of our projects, we upgraded Goldengate version to 12.2.0.1. After upgrading to newer version, I am able to successfully add new replicats. But when I […]

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Goldengate – Integrated Capture fails with OGG-02912

Here is one of my recent experiences running Oracle Goldegange 12.2.0.1 against Oracle 11.2.0.4 database. I was able to add Goldengate Extract Integrated process successfully without any […]

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oracle impdp as sysdba and attach job

impdp allows Oracle DBA to exit out of the current process while the job continues to run in the background.  In the event you have to connect to the […]

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oracle – generate kill database sessions script

Here is the script that comes handy to Oracle DBAs for generating script to kill sessions based on user sessions.

For example, this SQL script generates the script to kill […]

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Oracle dbms_job remove from another schema

In the following use case, as sysdba I am trying to remove the job that belongs to another user – ‘AMS2000’ that results in error – ORA-23421.

As a sysdba, […]

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Enabling and Disabling – auto optimizer stats collection

Here is how you can query if the Auto Optimizer Stats Collection job is running in Oracle Database 11g:

Login to database as SYSDBA:

SELECT CLIENT_NAME,
STATUS
FROM DBA_AUTOTASK_CLIENT
WHERE CLIENT_NAME = ‘auto optimizer […]

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oracle standard edition one vs oracle standard edition 2

Starting Sept 2015, Oracle Standard Edition and Oracle Standard Edition One are no longer available from Oracle.  Oracle Standard Edition 2 is the new product offering under standard edition […]

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Goldengate Integrated Extract – Identifying and resolving extract process hang issue

Goldengate extract process can hang for various reasons. It is very important to have a process in place to monitor goldengate process and detect hanging issues. I recently encountered […]

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expdp fails with ORA-27037 on Oracle RAC

When parallel option is used in expdp, it expects the DIRECTORY path to be available on nodes of the cluster. If you have created the directory on only […]

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Identifying Blocking Sessions in Oracle Database

Below SQL gives the blocker and blockee sessions in database.

Oracle RAC Environment:

select
(select username from gv$session where sid=a.sid) blocker,
a.sid,
'is blocking',
(select username from gv$session where sid=b.sid) blockee,
b.sid
from gv$lock a, gv$lock b
where [...]

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oracle archive log history

Here is the oracle sql script that comes handy to find out number of archive logs that are generated by database by day by hour.

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Deleting files older than x number of day

Below is the linux command to delete files older than 3 days with extension .trc:

find . -type f -name '*.trc' -mtime +3 | xargs -i -t rm {}

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Hello World!

Hi guys, if like me you’re a newbie to Angular JS and you’re trawling through the internet to find comprehensive materials to understand Angular […]

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expdp as sysdba

Here is the simple command to run expdp (data pump export) as sysdba.

expdp \"/as sysdba\" parfile=exp_user.par

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expdp as sysdba

Here is the simple command to run oracle logical backup/datapump export using sysdba:

expdp "/as sysdba" parfile=exp_user.par

 

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Oracle – AWR, ASH and ADDM reports for RAC

Following are the scripts that can be executed as sysdba in order to get the AWR, ASH and ADDM reports on Oracle RAC:

SQL script for getting AWR Report on […]

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openstack learning resources

Interested in learning more about openstack? following are some useful learning resources on openstack.
Thank you, Tyler Britten for sharing this information.

DevStack:
http://docs.openstack.org/developer/devstack/

Fuel with Virtualbox:
https://docs.mirantis.com/openstack/fuel/fuel-6.1/virtualbox.html

TryStack
http://trystack.org/

Join the Foundation:
https://www.openstack.org/join/register/?membership-type=foundation

Build your first OpenStack App:
https://www.openstack.org/summit/vancouver-2015/summit-videos/presentation/build-and-operate-your-first-openstack-application

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Preventing ssh session timeout using putty

For users who use putty.exe to connect to ssh can use the following setting in Putty to keep the session live.

Putty -> Change Settings -> Connection

Oracle Database consistent backup using expdp

Use the following procedure to take the consistent backup using expdp (oracle’s datapump export utility)

Stop application activity(transactions) against database.  This will ensure you that you don’t loose any transactions […]

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Setting Oracle Database User Password Not to Expire

password2.svg-rect4624-891

Here are the steps to set the password not to expire for the  Oracle database user. Here we are assuming that the user has been assigned with the default profile:

SQL> alter profile default limit password_life_time unlimited;

Profile altered.

[…]

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Oracle Tablespace/Data File Creation Time

password2.svg-rect8407-926

Ever wondered how to find out when the oracle database tablespace or data file was created?The following data dictionary synonym […]

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Simple steps to counter cyber threats

Cyber threats nowadays are incredibly sophisticated, unknown and unpredictable. Companies have to build a strong defence to counter cyber threats and these include:

Network security: Configure your network (routers and […]

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AngularJS learning resources

Here are the links that I compiled that can be useful to others who are interested in learning AngularJS.

https://docs.angularjs.org/tutorial

https://egghead.io/articles/new-to-angularjs-start-learning-here

https://thinkster.io/angulartutorial/mean-stack-tutorial/

https://www.udemy.com/angularjs-jumpstart/?couponCode=codewithdan

http://weblogs.asp.net/dwahlin/learning-angularjs-by-example-the-customer-manager-application

http://www.toptal.com/angular-js/a-step-by-step-guide-to-your-first-angularjs-app

http://joelhooks.com/blog/2013/08/03/learn-angularjs-in-a-weekend/

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Unix One Liner to Search and Replace a String in Multiple Files

Below is the unix oneliner to search and replace string in all files with extension .txt:

perl -pi -e "s/<search string >/<replace string >/g" *.txt

Example to search and replace string […]

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Oracle Tablespace Utilization by Schema Name

Oracle tablespace utilization script.

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Launch of ibisVC.com

With the launch of ibisVC.com, Princeton IT Services makes solid entry into SMB market offering Web Application/Software development services.

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Ssh Login Password Prompt Too Slow

Recently, I experienced an issue with ssh authentication – password prompt taking too long on one of the linux servers.  After some research on internet, I found the solution […]

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Princeton IT Services at Big Data and Data Science Symposium- NYU Shanghai

Princeton IT Services at Big Data and Data Science Symposium- NYU Shanghai

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Linux One Liner to Kill Multiple Process

Here is the linux one liner to kill multiple process using grep,awk:


ps -aef | grep < process name > |grep -v grep|awk '{print $2}' |xargs kill -9 $2

Here is […]

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Generating User Script from Oracle Database

generating the create user script from the data dictionary.

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Princeton IT Services is hosting NJ Hadoop meetup on YARN (Hadoop 2.0) + Docker containers – Integration and Privilege Isolation

Princeton IT Services is hosting NJ Hadoop meetup on YARN (Hadoop 2.0) + Docker containers - Integration and Privilege Isolation

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Princeton IT Services Pvt. Ltd is title sponsors of MBhavishya’14

Princeton IT Services Pvt. Ltd is title sponsors of MBhavishya’14, an IT Meet organized by MCA Department of Loyola Academy for Degree and PG College, Secunderabad on 15th November 2014. The primary objective of this Meet is to bring together students of Information Technology together to acquaint themselves with recent trends in the field of cutting edge technology of Mobile Computing.

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Training on Big Data/Apache Hadoop at Loyola Academy

We are conducting Big Data /Apache Hadoop Training Classes for 28 students of MCA Final year students of Loyola Academy Degree and PG College at their college premises at […]

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Workshop on SMAC conducted by Princeton for PG students at Loyola College, Hyderabad

On 7th October 2014 our COO - Suresh Eswar Bulusu has delivered workshop on SMAC (Social, Mobile, Analytics and Cloud Services) to MCA Final year students of Loyola Academy Degree and PG College at their college premises at Old Alwal, Secunderabad.

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Removing Linux Bash ShellShocker Malware

Removing Linux Malware possibly caused from Bash Shell Shocker attack.

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Princeton ITS – Infographic on Software Development

Princeton IT Services releases infographic on Software Development Services.

[…]

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Princeton IT Service is hosting NJ Hadoop meetup on Apache Slider and Ambari

Apache Ambari project is aimed at making Hadoop management simpler for provisioning, managing, and monitoring Apache Hadoop clusters. Apache Slider project is a YARN application used to deploy existing distributed applications on YARN to manage and monitor applications at run time.

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Hadoop on Android

Android and Hadoop are two technologies to talk about. These individual technologies solve many real time problems.

“How about combining them ?” is a question for people interested in future development of technology.

[…]

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Import data from Oracle Database to HDFS using Sqoop

Sqoop is a command-line interface application for transferring data between relational databases and Hadoop. Sqoop Helps in efficiently transferring bulk data between Hadoop and the Oracle database.

[…]

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Using Counters in MapReduce to Track Bad Records

The MapReduce framework provides Counters as an efficient mechanism for tracking the occurrences of global events within the map and reduces the phases of jobs. For example, a typical MapReduce job will kick off several mapper instances, one for each block of the input data, all running the same code. These instances are part of the same job, but run independent of one another. Counters allow a developer to track aggregated events from all of those separate instances. A more concrete use of Counters can be found in the MapReduce framework itself. Each MapReduce job defines several standard Counters. The output of these Counters can be found in the job details of the Job Tracker web UI.

[…]

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Integrate HIVE with HBase and Query using IMPALA

HBase tables can be integrated with HIVE, so that querying can be done using IMPALA. IMPALA queries are pretty fast and as easy as any standard SQL queries. We shall load transactional data into HBase table integrated with HIVE using ImportTSV method, and then query the corresponding HIVE table from IMPALA.

[…]

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How to Configure Replication Factor and Block Size for HDFS?

Hadoop Distributed File System (HDFS) stores files as data blocks and distributes these blocks across the entire cluster. As HDFS was designed to be fault-tolerant and to run on commodity hardware, blocks are replicated a number of times to ensure high data availability. The replication factor is a property that can be set in the HDFS configuration file that will allow you to adjust the global replication factor for the entire cluster. For each block stored in HDFS, there will be n – 1 duplicated blocks distributed across the cluster. For example, if the replication factor was set to 3 (default value in HDFS) there would be one original block and two replicas.

[…]

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Loading Customer Data into HBase using a PIG script

There are different ways to load data into HBase tables like:
‘put’ to manually load data records into HBase, ImportTSV and bulk load options.

Alternatively, lets try to load huge customer data file into HBase using Apache PIG.
The data set has the following fields:

[…]

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Using MRUnit to Develop and Test MapReduce Jobs

Conceptually, MapReduce jobs are relatively simple. In the map phase, each input record has a function applied to it, resulting in one or more key-value pairs. The reduce phase receives a group of the key-value pairs and performs some function over that group. Testing mappers and reducers should be as easy as testing any other function. A given input will result in an expected output. The complexities arise due to the distributed nature of Hadoop. Hadoop is a large framework with many moving parts. Prior to the release of MRUnit by Cloudera, even the simplest tests running in local mode would have to read from the disk and take several seconds each to set up and run.

[…]

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Using FileSystem API to read and write data to HDFS

Reading data from and writing data to Hadoop Distributed File System (HDFS) can be done in a lot of ways. Now let us start by using the FileSystem API to create and write to a file in HDFS, followed by an application to read a file from HDFS and write it back to the local file system.

[…]

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33 Frequently used HDFS shell commands

# Open a terminal window to the current working directory.
# /home/training

# 1. Print the Hadoop version
hadoop version

# 2. List the contents of the root directory in HDFS
#
hadoop fs -ls /

# 3. Report the amount of space used and
# available on currently mounted filesystem
#
hadoop fs -df hdfs:/

# 4. Count the number of directories,files and bytes under
# the paths that match the specified file pattern
#
hadoop fs -count hdfs:/

[…]

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Computing Moving-Average of Stocks in Hadoop HIVE

General Sense of Moving Average:

Moving Average is a widely used indicator in technical analysis that helps smooth out price action by filtering out the “noise” from random price fluctuations. A moving average (MA) is a trend-following or lagging indicator because it is based on past prices.

[…]

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Princeton IT Service is hosting NJ Hadoop – Apache Storm meetup.

Storm is a distributed and high-performance real-timecomputation system used by Twitter, Yahoo, Spotify, WebMD. Storm is a top level Apache Project which brings brand, governance and large community of the Apache Software Foundation. Storm scales linearly, fault-tolerant, provides areliable processing semantics, and is language agnostic (e.g. Java, Ruby, Python, Javascript, Perl)

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Analyse Hadoop fsimage using the Offline Image Viewer (OIV) Tool

Hadoop fsimage  is an “Image” file and its contents cannot be read easily using normal unix file system tools like cat, more etc. At times, it is very important to read the clear text version of the fsimage which holds the meta data of the file system. You can perform NameSpace Analysis, find out health of your fsimage, and even explore the interesting usage patterns.

[…]

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Hadoop MapReduce Streaming Using Bash Script.

MapReduce has a feature known as Hadoop Streaming that gives the flexibility to write code in your favorite language other than Java. You can use Ruby, Perl, Python or even quickly write a MapReduce job using shell script.

[…]

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Demystifying MapReduce: Python MR Solution

The following Python code mapper.py will take the text file as input and tokenize it to create a set of <key, value> pairs. The key will be a number reflecting the no. of characters in each word, and the value will be the word itself.

[…]

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Fixing the External USB drive Error “Drive not accessible. The parameter is incorrect”

Fixing the external USB drive error "Drive not accessible. The parameter is incorrect"

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How to make the Namenode leave Safemode?

How to make the Namenode leave safemode?

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Various commands to determine the type of File System drive from Linux Terminal

The following are the various commands to ascertain the type of file system drive in Linux Operating System

#  df –T
# mount
#  cat /etc/fstab
#  fsck -N /dev/sdc1
#  sudo file -s […]

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Networking Bandwidth Testing

Networking bandwidth testing

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Networking : Whats the VLAN ID?

Networking : Whats the VLAN ID

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IPTables – Opening up Multiple Ports – One Liner

#—for all subnets / tcp protocol—#
#iptables -A INPUT -m state --state NEW -m tcp -p tcp -s 192.168.122.0/24 --match multiport --dports 22,25,123,53

#—for subnet – 192.168.122.0/24 / tcp protocol —#
#iptables [...]

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Linux – Top Ten Processes with High Memory Usage

Finding top ten process on linux with high memory usage.

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Fixing NTP time issue on CentOS 6

Here are the steps that I followed in order to fix the timezone sync issue on Cent OS 6 linux:

[…]

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Opening Port on Iptables

By default iptables is the firewall that is enabled on linux systems. It is very simple to open ports without totally disabling the iptables service. Here are simple steps:

iptables [...]

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Increasing SSH Timeouts

Here are the steps to increase ssh timeout at the server level on Linux OS:

These steps are performed on CentOS:

Modify the following directives by editing the sshd config file: […]

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Princeton ITS partners with Synology

Princeton ITS is proud to announce partnership with Synology to provide NAS solutions to Small and Medium Businesses.

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AWK one liner – Getting Sum of a Column

The following AWK one liner that can be used to get sum of a column in a text file:

Here is the sample of file content:

cat file_size.txt

-rw——- 1 oracle oinstall […]

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Team Building

Frames_front_door

 

Today, Princeton IT Services conducted a team building event at Frames Bowling Lounge near Port Authority in New York City […]

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Princeton ITS is hosting NJ Hadoop Meetup – Cassandra – High Performance and Big Data Solution.

Topic: Cassandra – High Performance Big Data Solution

Guest Speaker: Edward Capriolo.

Time: Tuesday,  May 14th , 2013, 7:00 PM

Location: Princeton IT Services, Inc., 3525 Quakerbridge Rd, Suite#1400, Hamilton, New Jersey, 08619

[…]

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Launching Our New Website

We are excited to launch our new website of Princeton IT Services on April 15, 2013. We have made fundamental changes in all pages and the entire layout. It […]

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