Category Archives: NoSQL

Databases, that fall outside the of the Relational Database.

MongoDB Script for counting records in collections in all the databases

Here is a quick script. I wrote for a co-worker.

var host = "localhost"
var port = 27000
var dbslist = db.adminCommand('listDatabases');

for( var d = 0; d < dbslist.databases.length; d++) {
     var db = connect(host+":"+port+"/"+dbslist.databases[d].name);
     var collections = db.getCollectionNames();
     for(var i = 0; i < collections.length; i++){
         var name = collections[i];
         if(name.substr(0, 6) != 'system') {
            print("\t"+dbslist.databases[d].name+"."+name + ' = ' + db[name].count() + ' records');
         }
     }
}

 

Elasticsearch

Elasticsearch is a distributed restful search and analytic tool that is built on the top of Apache Lucene for high performance.

Elasticsearch features include:

Real-Time Data Indexing
Scalability
High Availability
Multi-Tenancy
Full Text Search
Document Orientation

The flow of data never stops so the question is how quickly can that data become available. Elasticsearch indexes the data in real-time allowing the for data to be made available as quickly as it can for real-time analytics.

Elasticsearch is horizontally scalable. An organization can simply add nodes to expand the cluster capacity. Elasticsearch is resilient in detecting and removing failed nodes and rebalancing itself to ensure that an organization’s data is safe and accessible.

Elasticsearch can also host multiple indices that can be queried independently or as a group. Elasticsearch structures it’s data in JSON documents. All fields are indexed by default and all the indices can be used in a single query.

Clients can connect to Elasticsearch by using a standard HTTP REST library. This gives any programming language the ability to connect to Elasticsearch.

Elasticsearch has been used to query 24 billion records in 900ms. It’s currently being used by companies such as Github, Foursquare, and Xing.

website: http://www.elasticsearch.org/