MongoDB Basics Introduction along with MapReduce

MongoDB Basics Introduction along with MapReduce

• 1.
  An introduction toMongoDB Rácz Gábor ELTE IK, 2013. febr. 10.
• 2.
  2 In Production http://www.mongodb.org/about/production-deployments/
• 3.
  3 NoSQL • Key-value • Graphdatabase • Document-oriented • Column family
• 4.
  4 Document store RDBMS MongoDB DatabaseDatabase Table, View Collection Row Document (JSON, BSON) Column Field Index Index Join Embedded Document Foreign Key Reference Partition Shard
• 5.
  5 Document store RDBMS MongoDB DatabaseDatabase Table, View Collection Row Document (JSON, BSON) Column Field Index Index Join Embedded Document Foreign Key Reference Partition Shard > db.user.findOne({age:39}) { "_id" : ObjectId("5114e0bd42…"), "first" : "John", "last" : "Doe", "age" : 39, "interests" : [ "Reading", "Mountain Biking ] "favorites": { "color": "Blue", "sport": "Soccer"} }
• 6.
  6 CRUD • Create • db.collection.insert(<document> ) • db.collection.save( <document> ) • db.collection.update( <query>, <update>, { upsert: true } ) • Read • db.collection.find( <query>, <projection> ) • db.collection.findOne( <query>, <projection> ) • Update • db.collection.update( <query>, <update>, <options> ) • Delete • db.collection.remove( <query>, <justOne> )
• 7.
  7 CRUD example > db.user.insert({ first:"John", last : "Doe", age: 39 }) > db.user.find () { "_id" : ObjectId("51…"), "first" : "John", "last" : "Doe", "age" : 39 } > db.user.update( {"_id" : ObjectId("51…")}, { $set: { age: 40, salary: 7000} } ) > db.user.remove({ "first": /^J/ })
• 8.
  8 Features • Document-Oriented storege •Full Index Support • Replication & High Availability • Auto-Sharding • Querying • Fast In-Place Updates • Map/Reduce Agile Scalable
• 9.
  9 Memory Mapped Files •„A memory-mapped file is a segment of virtual memory which has been assigned a direct byte-for-byte correlation with some portion of a file or file-like resource.”1 • mmap() 1: http://en.wikipedia.org/wiki/Memory-mapped_file
• 10.
  10 Replica Sets • Redundancyand Failover • Zero downtime for upgrades and maintaince • Master-slave replication • Strong Consistency • Delayed Consistency • Geospatial features Host1:10000 Host2:10001 Host3:10002 replica1 Client
• 11.
  11 Sharding • Partition yourdata • Scale write throughput • Increase capacity • Auto-balancing Host1:10000 Host2:10010 Host3:20000 shard1 shard2 Host4:30000 configdb Client
• 12.
  12 Mixed Host4:10010 Host5:20000 shard1 shardn Host6:30000 configdb Client Host1:10000 Host2:10001 Host3:10002 replica1 Host7:30000 ...
• 13.
  13 Map/Reduce db.collection.mapReduce( <mapfunction>, <reducefunction>, { out: <collection>, query: <>, sort:<>, limit: <number>, finalize: <function>, scope: <>, jsMode: <boolean>, verbose: <boolean> } ) var mapFunction1 = function() { emit(this.cust_id, this.price); }; var reduceFunction1 = function(keyCustId, valuesPrices) { return sum(valuesPrices); };
• 14.
  14 Other features • Easyto install and use • Detailed documentation • Various APIs • JavaScript, Python, Ruby, Perl, Java, Java, Scala, C#, C++, Haskell, Erlang • Community • Open source
• 15.
  15 Theory of noSQL:CAP CAP Theorem: satisfying all three at the same time is impossible A P • Many nodes • Nodes contain replicas of partitions of data • Consistency • all replicas contain the same version of data • Availability • system remains operational on failing nodes • Partition tolarence • multiple entry points • system remains operational on system split C
• 16.
  16 Theory of noSQL:CAP CAP Theorem: satisfying all three at the same time is impossible A P • Many nodes • Nodes contain replicas of partitions of data • Consistency • all replicas contain the same version of data • Availability • system remains operational on failing nodes • Partition tolarence • multiple entry points • system remains operational on system split C
• 17.
  17 ACID - BASE Pritchett,D.: BASE: An Acid Alternative (queue.acm.org/detail.cfm?id=1394128) • Atomicity • Consistency • Isolation • Durability • Basically Available (CP) • Soft-state • Eventually consistent (AP)
• 18.
  18 Thank you foryour attention!