Linux on Windows - Subsystem for Linux Setup

If you miss UNIX while working on Windows or would like to try experimenting with unix, Windows 10 offers an impressive feature that is worth exploring.

You can now install Windows Sub System for Linux (WSL) on Windows10 with a Linux distribution of your choice. As of now, the supported distributions are Ubuntu, SUSE, Kali and Debian. More info on this feature can be found here..

This subsystem seems to be very light weight and is definitely a better option than having to run the full Virtual Machine on window server.(!! requires developer option to be enabled on your machine !!). 

Here is a quick note on the setup and few tests using some specific features..

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Written by rajkiran on Saturday August 4, 2018

Image: 2018-08/faucet1.jpg

Let's Spell - Alexa Skill Demo Video

Here is the little fun video demo to spell the words with the Alexa Skill  Let's Spell 

After invoking the skill, you can use the following commands to interact with the App. 
- Alexa, "I Spell" / "My Turn"
- Alexa, "U Spell" / "Your Turn"

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Written by rajkiran on Monday July 30, 2018

Image: 2018-07/lets-spell-plain1.png

OpenProject installation on Ubuntu with Postgresql and Apache / Nginx

In this note, let's do a quick review on the installation of the very popular open source OpenProject software with Postgresql database and Apache/Nginx webservers. Open Project software has plenty of features, needed for managing the entire project life cycle and is offered with the Community Edition and Enterprise licenses.

The openproject installer for ubuntu configures mysql database and apache webserver by default. We will need to do little bit customization in order to use postgresql as the database for the repository and also check the basic configuration needed to get access to the web UI with either apache or the nginx webserver.

Configuration Info

Operating System : Ubuntu 16.04 ( Xenial )
Database : Postgresql 9.15.2
Web Server : Apache / Nginx
Open Project :  Community Edition

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Written by rajkiran on Saturday June 23, 2018

Image: 2018-06/niagara-600.jpg

Alexa Siri - Element Info chat

Here is the video with a fun chat between the Siri Voice and Alexa about the Element Info ????

Element Info skill can be accessed in multiple ways, Alexa skill can be invoked with the following command. 

To invoke the skill --> "Alexa, open Element Info" 
Learn Mode --> "Teach Me" 
Quiz Mode --> "Quiz Me" 

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Written by rajkiran on Tuesday April 3, 2018

Image: 2018-06/1528429384_element-info-hekash-sm.png

Oracle 12c - Temporal Validity


Temporal validity feature allows you to add a valid time dimension to the table data by specifiying the start and end datetimes of the period for which the data should be valid and visible.
Flashback query clauses ASOF, VERSIONS can be used to query the data valid for a specified period of time. You can also control the data visibility at the session level by using the DBMS_FLASHBACK_ARCHIVE.enable_at_valid_time procedure.

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Written by rajkiran on Monday June 9, 2014

Image: 2018-06/circuits-1.jpg

Oracle 12c - In-Database Archiving

In-Database Archiving, one of the many exciting 12c features, allows you to selectively archive the data that is no longer needed for the application, yet you can keep it online along with other active data within the same database for the audit compliance.  
In order to access the archived data, all you need to do is just change the visibility setting for the session. This will greatly save you from all the tedious process of the tape backup restore and loading the data back to the database.
Even though the archived data is not displayed by default, it is still residing within the same table and will still be validated for all the constraint rules similar to the active data. Also, it is recommended to compress the archived data to prevent any application query and backup performance issues.
Here is a small demo for this feature.

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Written by rajkiran on Monday June 9, 2014

Image: 2018-06/earphone-1.jpg

Oracle 12c - PDB Administration



Here are some of the examples showing various PDB Administration activities...

{slider Create a new PDB From SEED}

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Written by rajkiran on Monday June 9, 2014

Image: 2018-06/faucet-2.jpg

Oracle 12c - Non-CDB & CDB

In 12c, for the database creation, you have the option to choose either a non-container database (non-CDB --> pre12c architecture) or a Container database (CDB --> 12c multitenancy architecture). You can easily migrate a non-CDB database into a CDB database. However, You will not be able to migrate a CDB database back to the old architecture, non-CDB database.

By default, database will be created in pre12c mode. "Enable Pluggable Database" clause needs to be used inorder to make it as a CDB.

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Written by rajkiran on Monday June 9, 2014

Image: 2018-06/budha-1.jpg

Oracle 12c - Multi Tenancy Architecture

The most exciting feature in 12c is the multi tenancy architecture which will greatly benefit in the database consolidation with reduction in the overhead of resources needed for maintaining multiple instances and easing up lot of DBA administration activities
For backward compatibility, 12c still supports the traditional architecture. You have to explicitly choose the new architecture option when creating new database.

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Written by rajkiran on Sunday June 8, 2014

Image: 2018-06/ripple-2.jpg

Oracle 12c - Oracle Home Cloning

This note is about cloning and configuring an existing Oracle Home to a new location either on the same server or a different server. Cloning is much quicker especially when you are required to setup multiple database installations.

In this example, an existing Oracle Home on the server, 'kirlinc' is cloned to another server, 'kirlinb' with a different Oracle Home directory.

kirlinc: /data/oracle/app/oracle/product/12.1.0 --> kirlinb:/data/oracle/app/oracle/product/12R1

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Written by rajkiran on Sunday June 8, 2014

Image: 2018-06/faucet-1.jpg