mongodb at community engine
DESCRIPTION
This talk will cover lessons learned at Community Engine regarding MongoDB, including: why we moved away from an Hybrid solution using SQL and MongoDB; an outline of the technologies and what we learned using MongoDB on Amazon Web Services; the MongoDB C# driver; MongoDB with SOLR for Full Text Search; how we do migration, deployment and more.TRANSCRIPT
MongoDB at
Community Engine
Agenda
Brain dump on our experience with MongoDB• Why NoSQL• Why we chose MongoDB• Moving away from an hybrid solution• MongoDB and Amazon• SOLR and MongoDB• Ease of development• Zero downtime database deployment
About Community Engine• Social network based on locality and
small business• Launching in April• Built on:
• ASP.NET MVC 3• Amazon Web services• MongoDB• SOLR• Mahout• …
NoSQL?
• How to store the big amounts of data required in social networking applications
• Data complexity, NoSQL handle hierarchical and graph data structures better
• Change management is always difficult with RDBMS
• Scaling
Why we chose MongoDB?
• Reviewed different products RavenDB, CouchDB...• Selected MongoDB because we had the best
experience– Very easy to install and get started– Great developer experience– Replication very easy to setup– Good documentation– Much of the convenience of SQL, Dynamic
Queries, Indexing
Why Hybrid?
• Team had a lot of experience with SQL Server and Entity Framework
• Reporting• Transaction
No more SQL Server• Simplify our infrastructure• Easier to Backup• Better performance, not slowed down by SQL
Server, too many queries joined in the application
• Development speed• Lower cost
Transaction?
Transactions we could go around that using the atomic document updates and a good schema design
MongoDB supports atomic operations on single document.
When transactions across documents are neededTwo phase commits
Hosting with Amazon Web Service
• Elasticity and scalability• Configure MongoDB using Amazon EC2 instance
bundled into an AMI.• 64 bits EC2 instance• Raid10 + EBS volumes• Multi-datacenter 3-node replica set in different
availability zone• Use secondaries for zero downtime backup• We are not yet using sharded replica sets
What about durability?
Use journalingUse replica sets
Critical writes
Verify that replication is working at write time
mongodb://host1,host2,host3/?safe=true;w=2;
•safe=true : Use safemode•w=2: wmode, connect to a replica set waiting for replication to succeed on the majority of nodes
Why we kept SOLR?
• Right tool for the right job• Proven technology• SOLR best solution for Full Text Indexing• Faceted search, Spelling suggestions… • Team already skilled with SOLR• SOLR scales well
MongoDB/SOLR How we do it
MongoDB/SOLR How we do it
MongoDB/SOLR How we do it
MongoDB/SOLR How we do it
MongoDB/SOLR How we do it
Ease of development
Hierarchical data in SQL Server
Single table
Mongo Database Schema
Using Type discriminator
{"_id" : ObjectId("4f504e7acd3e1c190ce04198"),"_t" : "PhotoSpark","Photo" : "MyMotorcycle.png ""DateCreated" : ISODate("2012-02-24T09:23:12.246Z")
}{
"_id" : ObjectId("4f504e7ccd3e1c190ce04199"),"_t" : "PostSpark","Body" : "Hello World“" DateCreated" : ISODate("2012-02-28T10:44:12.858Z")
}
Views
Deployment of database with zero downtime
• We release every week• We aim at zero downtime• Our domain model change often
Deployment of database with zero downtime
Make sure that our code can handle both "versions" of the data structure
When saving we updates to the new structure
Deployment of database with zero downtime
• Use a migration script
Expansion Script Deploy new version Compression Script
t
Deployment of database with zero downtime
Questions?
