Introduction to MongoDB on the Shell - Spencer Brody, Software Engineer, 10gen

MongoDallas 2011

A general introduction to MongoDB followed by an interactive session using the MongoDB shell with the emphasis on queries and schema design.

Transcript

1. Spencer Brody ©  Copyright  2010  10gen  Inc.  
2. Who Am I? •  Database Kernel Engineer at 10gen •  spencer@10gen.com •  @stbrody
3. 10 Key Performance Indicators 4 – 4:45pm Plaza B
4. Types of Non-Relational Data Models •  Key-value stores •  Document stores •  Column-oriented databases •  Graph databases
5. Terminology RDBMS   Mongo   Table,  View   Collection   Row(s)   BSON  Document   Index   Index   Partition   Shard   Partition  Key   Shard  Key  
6. Scaling MongoDB •  Replication – Availability and Durability •  Replica Sets •  Can also be used to scale reads •  Sharding – Read and write scalability •  Collections are sharded •  Each shard is served by its own replica set •  Shard key ranges are automatically balanced
7. MongoDB is a Single-Master System •  All writes are to a primary (master) •  Failure of the primary is detected, and a new one is elected •  Application writes get an error if there is no quorum to elect a new master •  Reads can continue
8. Consistency Models •  Single vs Multi-Master •  Strong vs eventual consistency
9. Single Master •  All writes go to a single master and then replicated •  Replication can provide read scalability •  Writing becomes a bottleneck •  Physical limitations (seek time) •  Throughput of a single I/O subsystem
10. Single Master - Sharding •  Partition the primary key space •  Set up a duplicate system for each shard •  The write-rate limitation now applies to each shard •  Can the data be re-sharded on a live system? •  Can shards be re-balanced on a live system?
11. Primary" Secondary" Secondary" Primary" Secondary" Secondary" Primary" Secondary" Secondary" Primary" Secondary" Secondary" Key Range" 0..30" Key Range" 31..60" Key Range" 61..90" Key Range" 91.. 100" MongoS" MongoS" MongoS" Read" Write" MongoS"
12. Documents Blog Post Document" " p = { author: “Spencer”," date: new Date()," title: “Introduction to MongoDB”," tags: [“NoSQL”, “Mongo”, “MongoDB”]}" " > db.posts.save(p)"
13. Querying >db.posts.find()" " { _id : ObjectId("4c4ba5c0672c685e5e8aabf3")," author : “spencer", " date : “Mon Jul 11 2011 19:47:11 GMT-0700 (PDT)", " title: “Introduction to MongoDB”," tags: [“NoSQL”, “Mongo”, “MongoDB”]} " "
14. Secondary Indexes Create index on any Field in Document" " // 1 means ascending, -1 means descending" " >db.posts.ensureIndex({author: 1})" " >db.posts.find({author: ʻspencer'}) " " { _id : ObjectId("4c4ba5c0672c685e5e8aabf3")," author : “spencer", " ... }"
15. Query Operators •  Conditional 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: /^spe*/i } )" " // count posts by author" > db.posts.find( {author: ʻspencerʼ} ).count()"
16. Atomic Operations •  $set, $unset, $inc, $push, $pushAll, $pull, $pullAll, $bit" > comment = { author: “fred”, " date: new Date()," text: “Interesting blog post”}" " > db.posts.update( { _id: “...” }, " " "{$push: {comments: comment}, " " " $inc: {numComments: 1}} );" "
17. Nested Documents { _id : ObjectId("4c4ba5c0672c685e5e8aabf3"), " author : “spencer"," date : “Mon Jul 11 2011 19:47:11 GMT-0700 (PDT)", " text : “Introduction to MongoDB"," tags : [ “NoSQL", “Mongo", “MongoDB" ]," numComments : 1," comments : [" "{" " "author : "Fred"," " "date : “Mon Jul 11 2011 20:51:03 GMT-0700 (PDT)"," " "text : “Interesting blog post"" "}" ]}"
18. Indexes // Index nested documents > db.posts.ensureIndex( “comments.author”:1 ) Ø db.posts.find({‘comments.author’:’Fred’}) // Index on tags > db.posts.ensureIndex( tags: 1) > db.posts.find( { tags: ’Mongo’ } ) // geospatial index > db.posts.ensureIndex( “author.location”: “2d” ) > db.posts.find( “author.location” : { $near : [22,42] } )
19. MongoDB – More •  Geo-spatial queries •  Require a geo index •  Find points near a given point •  Find points within a polygon/sphere •  Built-in Map-Reduce •  The caller provides map and reduce functions written in JavaScript
20. DEMO
21. MongoDB Access •  Drivers are available in many languages •  10gen supported •  C, C# (.Net), C++, Java, JavaScript, Perl, PHP, Python, Ruby, Scala •  Community supported •  Clojure, ColdFusion, F#, Go, Groovy, Lua, Node.js, R •  http://www.mongodb.org/display/DOCS/Overview+- +Writing+Drivers+and+Tools
22. MongoDB Availability •  Source •  https://github.com/mongodb/mongo •  Server •  License: AGPL •  http://www.mongodb.org/downloads •  Drivers •  License: Apache •  http://www.mongodb.org/display/DOCS/Drivers
23. @mongodb   ©  Copyright  2010  10gen  Inc.   conferences,  appearances,  and  meetups   http://www.10gen.com/events     http://bit.ly/mongoO     Facebook                    |                  Twitter                  |                  LinkedIn   http://linkd.in/joinmongo   download at mongodb.org We’re  Hiring  !   Engineers,  Sales,  Evangelist,  Marketing,  Support,  Developers    
24. •  Use cases •  Case studies Use cases and customers