Blog

The differences between KogScript running in Console and kogscript.exe

24

Feb
2017
Posted By : Michael Atkinson 0 Comment
KogScript, Lua, SQL, programming, how to, console window

KogScript is a general purpose programming language based on Lua. It may be run within Console, which acts as an integrated development environment for it, or run from the command line tool kogscript.exe.

The KogScript running within Console and via kogscript.exe are compiled from the same source files and are identical with the following exceptions.
 

sqldebug

In kogscript.exe the global variable sqldebug is set to 3. The sqldebug variable is used to control how much information is output on each sql query within the KogScript as it is executed. A level of 3 shows the query status, and table contents.

In Console sqldebug is not defined, so it acts as if it had a value of 0, this means … Read more

Read More

How to generate an identity / auto_increment column in Kognitio

17

Feb
2017
Posted By : Michael Atkinson 0 Comment

Occasionally we would like the value of the primary key field to be created automatically every time a new record is inserted. That is we would like an auto-incrementable field in a table.

What other databases do

Other databases use a variety of syntax to do this.

MySQL uses an AUTO_INCREMENT keyword, which is used within the table definition

CREATE TABLE fruit (
 ID int NOT NULL AUTO_INCREMENT,
 name varchar(255) NOT NULL,
 PRIMARY KEY (ID) );

 

The SQL Server syntax uses the IDENTITY keyword, again within the table definition, in this example starting at 1 and incrementing by 1.

CREATE TABLE city (
 ID int IDENTITY(1,1) PRIMARY KEY,
 
Read more

Read More

Kits, cats, sacks, wives: unfolding JSON data into tables

14

Feb
2017
Posted By : Graeme Cole 0 Comment
unfolding json data into tables, csv

Each wife had seven sacks…

Converting simple, flat JSON data into CSV or another tabular format is a problem addressed by many freely-available JSON-to-CSV converters. However, these are usually only useful when the JSON is a series of flat objects without any nested arrays.

In practice, real-world JSON files often have nested arrays containing more objects, each of which may contain arrays of their own. They tend to look like the old riddle As I was going to St Ives:

As I was going to St. Ives,
I met a man with seven wives.
Each wife had seven sacks,
Each sack had seven cats,
Each cat had seven kits.
Kits, cats, sacks, wives,
How many were there going to

Read more

Read More

What’s new in Kognitio Console version 80199s170123

07

Feb
2017
Posted By : Michael Atkinson 0 Comment
Whats new in Kognitio Console

SQL in expression contexts

 Up until this release SQL could only occur in Lua statements or assignments. For example in Kognitio Scripts we can write SQL within the script as a statement or assigning the results table to a variable.

drop table hr.employee;
t = select * from sys.ipe_user; 

This release of Kognitio Console adds the ability to place SQL in Lua expression contexts. So now within Kognitio Scripts we can place SQL in most places where a Lua expression may occur.

In the example below the data for the Kognitio users are read from the table sys.ipe_user as a Lua table. The rows element of that table is then passed to the apply function which passes each row

Read more

Read More

Playing Around With Kognitio On Hadoop: Hashes Cannot Always Anonymise Data

30

Jan
2017
Posted By : Chris Barratt 0 Comment
kognitio data scripts how to

In this brave new world of big data one has to be careful of the loss of privacy with the public release of large data sets. Recently I reread “On Taxis And and Rainbows” that presents an account of how the author came to de-anonymise a data set made available by New York City’s Taxi and Limousine Commission. This data set included logs of each journey made: locations and times of pickups and drop-offs along with supposedly anonymised medallion numbers and other data. The author came to identify the medallion number data as the MD5 check-sums of the medallion numbers. They were then able to compute a table mapping 22 million possible medallion numbers to their MD5 check-sums. They reported … Read more

Read More

Beginner tips for Kognitio scripting

24

Jan
2017
Posted By : Chak Leung Comments are off
Kognitio scripts, lua

Standard ANSI SQL, whilst a great language for database querying, doesn’t allow for commonly used features like looping or extensive variable usage. There are variants which support some of this e.g. Transact-SQL but not on Kognitio until the introduction of Kognitio scripts.

But 2 languages in one script? How does this work?

Kognitio scripts (also referred to as ‘Kog’ scripts) are based on the Lua language where SQL statements can be written together with Lua code for extra functionality. They allow typical procedural language operations without the need of extensive workarounds in a non-procedural language like SQL.

It can be a bit overwhelming for SQL only users so we’ll go over some useful tips for getting started, for more in … Read more

Read More

Using Kognitio on Amazon Elastic Map/Reduce

12

Jan
2017
Posted By : Andy MacLean Comments are off
Kognitio on Amazon EMR

Using Kognitio on Amazon Elastic Map Reduce

Amazon’s Elastic Map/Reduce product provides Hadoop clusters in the cloud. We’ve had several requests for the Hadoop version of our product to work with EMR. As of release 8.1.50-rel161221 we have made the two products compatible so you can use EMR to run Kognitio clusters. This article will show you how to get Kognitio clusters up and running on EMR.

In order to run Kognitio on EMR you will need:

This article assumes some basic familiarity with Amazon’s environment and the EMR … Read more

Read More

Getting the most from life

05

Jan
2017
Posted By : Ben Cohen Comments are off
getting the most from life

I am going to use Conway‘s Life to show off some of Kognitio’s features, including some which are new in version 8.1.50.

Life is a well-known toy problem so I won’t explain it in great detail beyond defining it. The rules are simple yet they lead to surprising emergent properties including periodic sequences and even a Turing machine:

  • At each of a sequence of time steps staring from zero, each cell in an infinite square lattice is either “alive” or “dead”.
  • At step zero there is a chosen starting configuration of dead or alive cells.
  • A dead cell will become alive in the next step if it has exactly 3 neighbours in the current step.
  • A living cell
Read more

Read More

Monitoring Kognitio from the Hadoop Resource Manager and HDFS Web UI

03

Jan
2017
Posted By : Alan Kerr Comments are off
monitoring kadoop clusters

If you’ve already installed Kognitio on your Hadoop distribution of choice, or are about to, then you should be aware that Kognitio includes full YARN integration allowing Kognitio to share the Hadoop hardware infrastructure and resources with other Hadoop applications and services.

Latest resoures for Kognitio on Hadoop:

Download:  http://kognitio.com/on-hadoop/

Forum:   http://www.kognitio.com/forums/viewforum.php?f=13

Install guide: (including Hadoop pre-requisites for Kognitio install):

http://www.kognitio.com/forums/Getting%20started%20with%20Kognitio%20on%20Hadoop.pdf

This means that YARN (https://hadoop.apache.org/docs/current/hadoop-yarn/hadoop-yarn-site/YARN.html)  (Hadoop’s preferred resource manager) remains in control of the resource allocation for the Kognitio cluster.

Kognitio clusters can be monitored from the apache YARN resource manager UI, and the HDFS name node UI.

You can reach the YARN resource manager UI from your Hadoop management interface -> YARN -> Web UI, or … Read more

Read More

Disk Space Connector

15

Dec
2016
Posted By : Mark Marsh Comments are off
disk space connector

The Kognitio external table connector scripts are a powerful way of accessing data from a wide variety of sources. Any data that can be presented as a stream of CSV information can be brought into Kognitio in a massively parallel operation and presented as a table. There is no restriction on the programming language – as long as the code can run on Linux, read stdin and write stdout and stderr it can be used. Typically BASH, Python or Perl will be used but for more advanced connectors, we have used Java and C / C++.

This blog post presents a very basic connector that loads data from the Linux df command (which displays disk usage figures). It runs a … Read more

Read More

Facebook

Twitter

LinkedId