Mongodb intro

IntroductionChristian Kvalheim - christkv@10gen.com @christkv

Todays Talk• Quick introduction to NoSQL• Some Background about mongoDB• Using mongoDB• Deploying mongoDB

Database Landscape memcached key/value scalability & performance RDBMS depth of functionality

What is NoSQL?Key / Value Column Graph Document

Key-Value Stores• A mapping from a key to a value• The store doesnt know anything about the the key or value• The store doesnt know anything about the insides of the value• Operations • Set, get, or delete a key-value pair

Column-Oriented Stores• Like a relational store, but ﬂipped around: all data for a column is kept together• An index provides a means to get a column value for a record• Operations:• Get, insert, delete records; updating ﬁelds• Streaming column data in and out of Hadoop

Graph Databases• Stores vertex-to-vertex edges• Operations: • Getting and setting edges • Sometimes possible to annotate vertices or edges• Query languages support ﬁnding paths between vertices, subject to various constraints

Document Stores• The store is a container for documents• Documents are made up of named fields • Fields may or may not have type definitions • e.g. XSDs for XML stores, vs. schema-less JSON stores• Can create "secondary indexes"• These provide the ability to query on any document field(s)• Operations:• Insert and delete documents• Update fields within documents

What is mongoDB?MongoDB is a scalable, high-performance,open source NoSQL database.• Document-oriented storage• Full Index Support• Replication & High Availability• Auto-Sharding• Querying• Fast In-Place Updates• Map/Reduce• GridFS

• Company behind mongoDB – (A)GPL license, own copyrights, engineering team – support, consulting, commercial license• Management – Google/DoubleClick, Oracle, Apple, NetApp – Funding: Sequoia, Union Square, Flybridge – Offices in NYC, Palo Alto, London, Dublin – 100+ employees

Where can you use it?MongoDB is Implemented in C++• Platforms 32/64 bit Windows, Linux, Mac OS-X, FreeBSD, SolarisDrivers are available in many languages10gen supported• C, C# (.Net), C++, Erlang, Haskell, Java, JavaScript, Perl, PHP, Python, Ruby, Scala, Node.JSCommunity supported• Clojure, ColdFusion, F#, Go, Groovy, Lua, R ... http://www.mongodb.org/display/DOCS/Drivers

History• First release – February 2009• v1.0 - August 2009• v1.2 - December 2009 – MapReduce, ++• v1.4 - March 2010 – Concurrency, Geo• V1.6 - August 2010 – Sharding, Replica Sets• V1.8 – March 2011 – Journaling, Geosphere• V2.0 - Sep 2011 – V1 Indexes, Concurrency• V2.2 - Soon - Aggregation, Concurrency

TerminologyRDBMS MongoDBTable CollectionRow(s) JSON DocumentIndex IndexJoin Embedding & LinkingPartition ShardPartition Key Shard Key

Documents Blog Post Document> p = { author: "Chris", date: new ISODate(), text: "About MongoDB...", tags: ["tech", "databases"]}> db.posts.save(p)

Querying> db.posts.find() { _id : ObjectId("4c4ba5c0672c685e5e8aabf3"), author : "Chris", date : ISODate("2012-02-02T11:52:27.442Z"), text : "About MongoDB...", tags : [ "tech", "databases" ] }Notes: _id is unique, but can be anything youd like

Introducing BSONJSON has powerful, but limited set of datatypes • arrays, objects, strings, numbers and nullBSON is a binary representation of JSON • Adds extra dataypes with Date, Int types, Id, … • Optimized for performance and navigational abilities • And compressionMongoDB sends and stores data in BSON • bsonspec.org

Secondary IndexesCreate index on any Field in Document// 1 means ascending, -1 means descending > db.posts.ensureIndex({author: 1})> db.posts.findOne({author: Chris}) { _id : ObjectId("4c4ba5c0672c685e5e8aabf3"), author: "Chris", ... }

Compound IndexesCreate index on multiple ﬁelds in a Document// 1 means ascending, -1 means descending > db.posts.ensureIndex({author: 1, ts: -1})> db.posts.find({author: Chris}).sort({ts: -1}) [{ _id : ObjectId("4c4ba5c0672c685e5e8aabf3"), author: "Chris", ...}, { _id : ObjectId("4f61d325c496820ceba84124"), author: "Chris", ...}]

Query OperatorsConditional Operators- $all, $exists, $mod, $ne, $in, $nin, $nor, $or, $size, $type- $lt, $lte, $gt, $gte// find posts with any tags> db.posts.find({tags: {$exists: true }})// find posts matching a regular expression> db.posts.find({author: /^ro*/i })// count posts by author> db.posts.find({author: Chris}).count()

Examine the query plan> db.posts.find({"author": Ross}).explain(){ "cursor" : "BtreeCursor author_1", "nscanned" : 1, "nscannedObjects" : 1, "n" : 1, "millis" : 0, "indexBounds" : { "author" : [ [ "Chris", "Chris" ] ] }}

Atomic Operations $set, $unset, $inc, $push, $pushAll, $pull, $pullAll, $bit// Create a comment> new_comment = { author: "Fred", date: new Date(), text: "Best Post Ever!"}// Add to post> db.posts.update({ _id: "..." }, {"$push": {comments: new_comment}, "$inc": {comments_count: 1} });

Nested Documents { _id : ObjectId("4c4ba5c0672c685e5e8aabf3"), author : "Chris", date : "Thu Feb 02 2012 11:50:01", text : "About MongoDB...", tags : [ "tech", "databases" ], comments : [{ author : "Fred", date : "Fri Feb 03 2012 13:23:11", text : "Best Post Ever!" }], comment_count : 1 }

Secondary Indexes// Index nested documents> db.posts.ensureIndex("comments.author": 1)> db.posts.find({"comments.author": "Fred"})// Index on tags (multi-key index)> db.posts.ensureIndex( tags: 1)> db.posts.find( { tags: "tech" } )

Geo • Geo-spatial queries • Require a geo index • Find points near a given point • Find points within a polygon/sphere// geospatial index> db.posts.ensureIndex( "author.location": "2d" )> db.posts.find( "author.location" : { $near : [22, 42] } )

Map Reduce The caller provides map and reduce functions written in JavaScript// Emit each tag> map = "this[tags].forEach( function(item) {emit(item, 1);} );"// Calculate totals> reduce = "function(key, values) { var total = 0; var valuesSize = values.length; for (var i=0; i < valuesSize; i++) { total += parseInt(values[i], 10); } return total; };

Map Reduce// run the map reduce> db.posts.mapReduce(map, reduce, {"out": { inline : 1}});{ "results" : [ {"_id" : "databases", "value" : 1}, {"_id" : "tech", "value" : 1 } ], "timeMillis" : 1, "counts" : { "input" : 1, "emit" : 2, "reduce" : 0, "output" : 2 }, "ok" : 1,}

Aggregation - coming in 2.2// Count tags> agg = db.posts.aggregate( {$unwind: "$tags"}, {$group : {_id : "$tags", count : {$sum: 1}}} )> agg.result [{"_id": "databases", "count": 1}, {"_id": "tech", "count": 1}]

GridFS Save ﬁles in mongoDB Stream data back to the client// (Python) Create a new instance of GridFS>>> fs = gridfs.GridFS(db)// Save file to mongo>>> my_image = open(my_image.jpg, r)>>> file_id = fs.put(my_image)// Read file>>> fs.get(file_id).read()

Rich Documents• Intuitive• Developer friendly• Encapsulates whole objects• Performant• They are scalable

Rich Documents{ _id : ObjectId("4c4ba5c0672c685e5e8aabf3"), line_items : [ { sku: tt-123, name: Coltrane: Impressions }, { ski: tt-457, name: Davis: Kind of Blue } ], address : { name: Banker, street: 111 Main, zip: 10010 }, payment: { cc: 4567, exp: Date(2012, 7, 7) }, subtotal: 2355}

Deployment• Single server - need a strong backup plan P

Deployment• Single server - need a strong backup plan P• Replica sets - High availability P S S - Automatic failover

Deployment• Single server - need a strong backup plan P• Replica sets - High availability P S S - Automatic failover• Sharded - Horizontally scale - Auto balancing P S S P S S

MongoDB Use Cases• Archiving• Content Management• Ecommerce• Finance• Gaming• Government• Metadata Storage• News & Media• Online Advertising• Online Collaboration• Real-time stats/analytics• Social Networks• Telecommunications

In Production

download at mongodb.org conferences, appearances, and meetups http://www.10gen.com/events Facebook | Twitter | LinkedInhttp://bit.ly/mongofb @mongodb http://linkd.in/joinmongo support, training, and this talk brought to you by

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Mongodb intro

by christkv on Apr 13, 2012

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