[MongoDB]: Different ways to Optimize your Cluster With Tag-Aware Sharding
MongoDB supports partitioning data using either a user-defined shard key index (composed of one or more fields present in all documents) or based on a hashed index on a single field (which also much be present in all documents). A…
[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…
[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…
[MySQL]: Load data infile
[root@dbversity tmp]# ll -lhtr CSV_* -rw-r–r– 1 oracle dba 298K Nov 26 02:39 CSV_DBV_HLDNGS.csv -rw-r–r– 1 oracle dba 489K Nov 26 02:40 CSV_DBV_DATA.csv -rw-r–r– 1 oracle dba 86K Nov 26 02:40 CSV_PS_RELN_BSNL.csv [root@dbversity tmp]# [root@dbversity tmp]# dos2unix CSV_* dos2unix: converting…
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…