Comparison between Mongo and Redis

nosql.md

NoSQL Discussion Points

Failover

• Master/Slave - Main Goal Data Redundancy
• Automated Failover - High Availability
• Good for D/R

Mongo

• All Data is Versioned

Data Types

• Mongo
  • JSON Style

{ author: 'joe',
  created : new Date('01/10/2012'),
  title : 'Yet another blog post',
  text : 'Here is the text...',
  tags : [ 'example', 'joe' ],
  comments : [ { author: 'jim', comment: 'I disagree' },
              { author: 'nancy', comment: 'Good post' }
  ]
}

• Redis
  • Strings, Lists, Sets, Hashsets
  • Everything is Key/Value
  • Supports complex operations

API

• Mongo
  • SQL Like (Native)
  • Reduce (JS)
  • Scala Support
  • Node Support
  • Supports notion of Indexs
  • Lacks Tx Support (Not an issue, b/c Akka wraps db calls in STM)

Sample Query

db.users.find({id:20202}) // Find User with id ..
db.users.find() // Find All
db.users.find({id:20202}, {first:1, last:1}) / Find first,last ...

val mongoColl = MongoConnection()("casbah_test")("test_data")
val user1 = MongoDBObject("user" -> "steve",
                          "email" -> "steve@gmail.com")
val user2 = MongoDBObject("user" -> "someOtherUser")
mongoColl += user1
mongoColl += user2
mongoColl.find()
// com.mongodb.casbah.MongoCursor =
// MongoCursor{Iterator[DBObject] with 2 objects.}

for { x <- mongoColl} yield x
/* Iterable[com.mongodb.DBObject] = List(
    { "_id" : { "$oid" : "4c3e2bec521142c87cc10fff"} ,
      "user" : "steve" ,
      "email" : "steve@gmail.com"},
     { "_id" : { "$oid" : "4c3e2bec521142c87dc10fff"} ,
      "user" : "someOtherUser"}
 ) */

• Mongo

r.set("key", "some value")
r.get("key") // Option[String] = Some(some value)

r.hmset("hash", Map("field1" -> "1", "field2" -> 2))
r.hmget[String,String]("hash", "field1", "field2") // Option[Map[String,String]] = Some(Map(field1 -> 1, field2 -> 2))

Other

• Mongo is Hugely Popular