Changing cluster name in Cassandra

As of 1.2.x you can do the following: 1. Start the cqlsh connected locally to the node. 2. Run: 3. Run nodetool flush on the node. 4. Update the cassandra.yaml file on the node, changing the cluster_name to the same as you set in step 2. 5. Restart the node. Please be aware that you [&hellip

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Restarting Jenkins

Jenkins is a wonderful CI tool the I rely on heavily for any project that I indeed to bring to fruition. However sometimes is can act a little funny, for example if you rename a project it will not display the build history from before the name change and may randomly drop the build history after [&hellip

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Parallel and Concurrent in regards to Garbage Collectors

Although the words “Parallel” and “Concurrent” are used synonymously, when used in reference to Java garbage collection they are not the same. Unfortunately is can often lead to confusion when developers delve into the the world of the JVM and garbage collection, so lets clear it up here. Parallel collector belongs to the family of pure-stop-the-world collectors. That [&hellip

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Book Review: Mastering ElasticSearch

I’ve been working with Elasticsearch in production for over a year now. So when I picked up this book I thought it would serve as a nice reference book when I needed it, I also know the authors from the community therefore had an idea that it would be a well-written and detailed book. I [&hellip

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Upgrading OpsCenter from 3.2 to 4.0 – Agent Trouble

I was running  DataStax OpsCenter version 3.2, once the 4.0 release was made available I began the install procedure. Eventything worked as expected until I attempted to install the new datastax-agents on the Cassandra nodes.     The option to ‘Fix’ was available, however the install process failed. The resulting log indicated that there was [&hellip

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Elasticsearch: Change in routing value resulting in duplicate documents

My current Elasticsearch project involves customers and orders. Customers and orders have a parent child relationship, with customer being the parent and order the child. The customer ID is used as the routing value, in some corner cases we are required to change the customer ID of an order. This is where it gets tricky. [&hellip

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Comments in JSON

Recently I was asked if you could write comments in JSON, just like you can in any common programming language. I was stumped for a second, I’ve never seen them, never wanted to comment my JSON so I needed to do some quick investigation to see if it was possible. Well it is, however there [&hellip

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Tip of the Day: MD5 Hash

When transferring files or making backups, be sure to create a hash of the file or files that you are operating on. This check ensures the integrity of the files you have been operating on are still intact once you are finished. There is built-in functionality to calculate and generate the hash value of MD5 without [&hellip

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DataStax Certified Cassandra Developer

I took and passed the DataStax Certified Cassandra Developer (DSCCD) exam a few weeks ago, that is offered by the company behind Cassandra, DataStax. It was a 90 minute exam in which I was required to answer 60 question, so 1.5 minutes per question, plenty of time. Personally I enjoyed taking the exam, it was nice to [&hellip

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Building Apache Spark with Scala 2.10

Apache Spark is an open source cluster computing system that aims to make data analytics fast — both fast to run and fast to write. The latest release is Spark 0.7.3. But this release requires Scala 2.9.3. If you are using Scala 2.10, this release would not work. Since Spark has not announced any Scala [&hellip

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