[MongoDB]: Writing Complex queries Using QueryBuilder
Writing Complex MongoDB Queries Using QueryBuilder MongoDB provides a lot of query selectors for filtering documents from a collection. Writing complex queries for MongoDB in Java can be tricky sometimes. Consider below data present in student_marks collection rs1:PRIMARY> db.dbversit.insert({“_id” :…
[MongoDB]: Linux ulimit Settings
How do we review and set resource limits : Here’s the command to see unlits is below [root@dbversitydotcom oracle]# ulimit -a core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited scheduling priority (-e) 0 file size (blocks,…
[Cassandra]: Overview andInstallation
Prerequisites : ============= Latest version of Oracle Java SE Runtime Environment (JRE) 7. Java Native Access (JNA) is required for production installations (latest version recommended). Python 2.6+ (needed if installing OpsCenter). If you are using an older RHEL-based Linux distribution,…
[MongoDB]: CSharp/.NET to test Auth
METHOD 1 : using System; using MongoDB.Bson; using MongoDB.Driver; using MongoDB.Driver.Builders; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication1 { class Program { static void Main(string[] args) { var connectionString = “mongodb://admin:pwd@dbversitydotcom/admin”; MongoClient client = new MongoClient(connectionString); MongoServer server…
[MongoDB]: Nested documents
Please refer my previous post for the background of the issues with nested documents at Issues-with-Nested-documents However, versions prior to 2.8-rc1 doesn’t handle nested documents properly – neither mongoimport nor mongoexport. But the good news is that both work with nested…
Lifecycle of a Node in Couchbase Server Demystified: Adding & Removing Nodes, Rebalancing & Failover
This blog was originally posted by Cihan Biyikoglu here on November 17th 2014 One of the top attributes of Couchbase Server is its simplicity when it comes to deploying and managing a cluster. Changing the topology of a cluster can be…
[MongoDB]: Different ways in Purging
There are three ways to do purging in MongoDB. Single collection, delete old entries Collection per day, drop old collections Database per day, drop old databases Option #1: single collection pros ==== Easy to implement Easy to run Map/Reduces cons…
Hadoop and MongoDB
What is Hadoop? Hadoop is a software technology designed for storing and processing large volumes of data using a cluster of commodity servers and commodity storage. Hadoop is an open-source Apache project started in 2005 by engineers at Yahoo. It…
The Elasticsearch ELK Stack
( E – Elasticsearch, L – Logstash , K – Kibana ) Elasticsearch ( search, analyze in real-time. sweet.) —————– Elasticsearch is a flexible and powerful open source, distributed, real-time search and analytics engine. Architected from the ground up for…