Walker Rowe – BMC Blogs https://www.bmc.com/blogs BMC Software Mon, 25 Mar 2019 11:06:27 +0000 en-US hourly 1 https://blogs.bmc.com/wp-content/uploads/2016/04/bmc_favicon-300x300-150x150.png Walker Rowe – BMC Blogs https://www.bmc.com/blogs 32 32 Introduction to the Neo4j Graph Database https://www.bmc.com/blogs/neo4j-graph-database/ Thu, 21 Mar 2019 00:00:44 +0000 https://www.bmc.com/blogs/?p=13707 Neo4j is a graph database. A graph database, instead of having rows and columns has nodes edges and properties. It is more suitable for certain big data and analytics applications than row and column databases or free-form JSON document databases for many use cases. A graph database is used to represent relationships. The most common […]]]> MongoDB vs Cassandra: NoSQL Databases Compared https://www.bmc.com/blogs/mongodb-vs-cassandra/ Fri, 08 Mar 2019 12:16:52 +0000 https://www.bmc.com/blogs/?p=13678 Here we make a side by side comparison of MongoDB versus Cassandra. We provide examples, with commands and code, and not just a narrative explanation. In sum, Cassandra is the modern version of the relational database, albeit where data is grouped by column instead of row, for fast retrieval. MongoDB stores records as documents in […]]]> How to Setup a MongoDB Cluster https://www.bmc.com/blogs/how-to-setup-mongodb-cluster/ Wed, 06 Mar 2019 00:00:17 +0000 https://www.bmc.com/blogs/?p=13667 Here we show how to set up a MongoDB cluster. In the previous post we showed how to install it on one machine. There are three pieces to install: config server query router shard server, i.e., database Looking at the diagram below, the mongos process runs as a router, meaning it tells clients where to […]]]> MongoDB Memory Usage and Management https://www.bmc.com/blogs/mongodb-memory-usage-and-management/ Wed, 27 Feb 2019 10:13:11 +0000 https://www.bmc.com/blogs/?p=13613 If you put too much data in your MongoDB database, it will run your server out of memory.  It can do that quickly too, so quick that you will not even be able to shutdown the mongo db process as the bash shell will no longer respond. The solution to this is add another node […]]]> How To Track Tweets by Geographic Location https://www.bmc.com/blogs/track-tweets-location/ Fri, 15 Feb 2019 00:00:06 +0000 https://www.bmc.com/blogs/?p=13570 Here we explain how to track users and tweets by their location. As we will see, there are some limits. (For more background on GEOJson, i.e., the universal standard to designate geographic location, you can read what we wrote about using locations in MongoDB here.) Twitter Users Must Opt into Location Tracking You can track […]]]> MongoDB GeoLocation Query Examples https://www.bmc.com/blogs/mongodb-geolocation-query-examples/ Thu, 07 Feb 2019 00:00:07 +0000 https://www.bmc.com/blogs/?p=13530 Here we explain how to query and working with geolocation data in MongoDB. GeoJSON is a universally-accepted standard to represent a location by its latitude and longitude, aka coordinates. MongoDB uses the same syntax as the US Geological Survey or other persons working with maps would use. For example, a simple point is represented like […]]]> How to Install MongoDB on Ubuntu and Mac https://www.bmc.com/blogs/how-to-install-mongodb-ubuntu-mac/ Wed, 23 Jan 2019 00:00:21 +0000 https://www.bmc.com/blogs/?p=13457 Here we explain how to install MongoDB in a stand-alone configuration on Ubuntu and Mac. Setting up a cluster is significantly more complicated. So we will explain that in another post. Install MongoDB on Ubuntu MongoDB comes in Free (Community), paid (Enterprise), and cloud (Atlas) editions. It’s not easy to find the free download on […]]]> The Differences Between Partition key, Composite key, and Clustering Columns in Cassandra https://www.bmc.com/blogs/cassandra-clustering-columns-partition-composite-key/ Mon, 21 Jan 2019 00:00:37 +0000 https://www.bmc.com/blogs/?p=13451 Here we explain the differences between partition key, composite key and clustering key in Cassandra. In brief, each table requires a unique primary key. The first field listed is the partition key, since its hashed value is used to determine the node to store the data. If those fields are wrapped in parentheses then the […]]]> Using Tokens to Distribute Cassandra Data https://www.bmc.com/blogs/cassandra-tokens/ Wed, 16 Jan 2019 00:00:51 +0000 https://www.bmc.com/blogs/?p=13444 Cassandra distributes data based on tokens. A token is the hashed value of the primary key. When you add nodes to Cassandra you assign a token range to each node, or let Cassandra do that for you. Then when you add data to Cassandra it calculates the token and uses that to figure out on which server […]]]> Configuring Apache Cassandra Data Consistency https://www.bmc.com/blogs/configuring-apache-cassandra-data-consistency/ Mon, 07 Jan 2019 00:00:19 +0000 https://www.bmc.com/blogs/?p=13400 Let’s look at how Apache Cassandra handles data consistency. If you write data to n – 1 nodes in a cluster and then an application reads it from node n Cassandra could report that the data is not there as replication is not instant. That could be a big problem or not a problem at […]]]>