Author Archives: tobias

SQL LIKE operation in Cassandra, is possible in v3.4+

For a long time it has not been possible to do a SELECT * FROM table WHERE firstname like ‘t%’; in Cassandra like you could in eg.. MySQL or any other Relation Database for that matter. In Cassandra v3.4 this … Continue reading

Posted in Uncategorized | 3 Comments

UDF/User Defined Functions in Cassandra 3.x

I was just playing around with Cassandra WRITETIME and thought it was somewhat difficult to figure out the date / timestamp of a number like this (microseconds since EPOC) 1470645914253000. So in my example it looked like this

So … Continue reading

Posted in Cassandra, JAVA | 1 Comment

Cassandra set the writetime explicitly with a PreparedStatement

This is a quick one, I wanted to set the writetime of a row explicitly when I populate the database for testing purposes. We use the writetime of a column to filter them out. It required some looking around to … Continue reading

Posted in Cassandra, JAVA, Scala | 1 Comment

Apache SPARK and Cassandra and SQL

This is a short intro to start using Apache SPARK with Cassandra, running SQL on the Cassandra tables. Note that I am not running a SPARK cluster, I am running “local”, to me this is really convenient, not having to … Continue reading

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SBT Good to know…

Dependecy problems I have been having some difficulties figuring out what depends on what. I found the following set plugins which I think can be really helpful; and Be sure to install GraphWiz first, I used Homebrew on … Continue reading

Posted in SBT, Scala | 1 Comment

Create an MBean (JMX) in Scala

Create the MBean like this

NOTE, that the interface/trait must end with MBean in the name And this is how you register your MBean

And the simply launch Java Mission Control (imc), attach to the JVM, and modify … Continue reading

Posted in Uncategorized | 2 Comments

SBT module not found, why ?

I have an build.sbt file that looks like this

But for some reason I can’t get slf4j downloaded from the Maven repository ( If I search the Maven Repository, I can clearly see that the version I intend to … Continue reading

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See who is connected to the same network / WIFI

There are tools out there, such as Angry IP Scanner, iNet or IP Scanner,  but this can easily be done using a bash script, not as nice looking perhaps but it does the job. The script :

Which should … Continue reading

Posted in Uncategorized | 1 Comment

Övervakning av min IVT-490 värmepump med Raspberry Pi

I denna artikeln ska jag försöka beskriva mitt lilla projekt med att övervaka min IVT-490 värmepump med en Raspberry P. Jag har hämtat mycket kunskap från dessa två forum-trådar : och Min värmepump har ett interface som ser … Continue reading

Posted in Raspberry Pi | 33 Comments

Calculate the minimum waste when cutting planks…

I made a web application which will calculate the most optimum layout of your pieces you would like to cut from a plank. This helps in figuring out how many planks of a certain size you would have to buy, … Continue reading

Posted in optimization, tool, web | Leave a comment