Introduction to MongoDB on the Shell - Scott Hernandez, Software Engineer, 10gen

MongoRaleigh 2011

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

About the Speaker: Scott Hernandez is a Software Engineer at 10gen, where he works on the Java driver, customer support, and many other things. He... is also one of the primary authors of Morphia, a Java ODM for MongoDB.

Transcript

1. Scott Hernandez ©  Copyright  2010  10gen  Inc.  
2. Release 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
3. Types of Non-Relational Data Models •  Key-value stores •  Document stores •  Column-oriented databases •  Graph databases
4. What is MongoDB •  Document Store •  Horizontally Scalable •  High Performance
5. MongoDB vs Traditional RDBMS databases   contain  rows   server   contain  tables     collections   documents   schema   joins  
6. Terminology RDBMS   Mongo   Table,  View   Collection   Row(s)   JSON  Document   Index   Index   Join   Embedded  Document   Partition   Shard   Partition  Key   Shard  Key  
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 •  Relational databases support transactions •  Can only see committed changes •  Commits/aborts span multiple changes •  Read-only transaction flavors •  Read committed, repeatable read, etc •  Single vs Multi-Master
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 via hashing •  Set up a duplicate system for each shard •  The write-rate limitation now applies to each shard •  Joins or aggregation across shards are problematic •  Can the data be re-sharded on a live system? •  Can shards be re-balanced on a live system?
11. MongoDB Storage Management •  Memory-mapped Database files •  Files are (pre)allocated as needed •  Indexes (B*-trees) point to documents
12. Documents Blog Post Document" " p = { author: “sridhar”," date: new Date()," title: “Using the C# driver with MongoDB”," tags: [“NoSQL”, “Mongo”, “MongoDB”]}" " > db.posts.save(p)"
13. Querying >db.posts.find()" " { _id : ObjectId("4c4ba5c0672c685e5e8aabf3")," author : “sridhar", " date : “Mon Jul 11 2011 19:47:11 GMT-0700 (PDT)", " title: “Using the C# driver with 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: ʻsridhar'}) " " { _id : ObjectId("4c4ba5c0672c685e5e8aabf3")," author : “sridhar", " ... }"
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: /^sri*/i } )" " // count posts by author" > db.posts.find( {author: ʻsridharʼ} ).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} );" "
17. Nested Documents { _id : ObjectId("4c4ba5c0672c685e5e8aabf3"), " author : “sridhar"," date : “Mon Jul 11 2011 19:47:11 GMT-0700 (PDT)", " text : “Using the C# driver with MongoDB"," tags : [ “NoSQL", “Mongo", “MongoDB" ]," 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. Scaling MongoDB •  Replication - Read scalability •  Master/Slave •  Replica Sets •  Sharding – Read and write scalability •  Collections are sharded •  Each shard is served by its own replica set •  Shard key ranges are automatically balanced
21. 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"
22. MongoDB Access •  Drivers are available in many languages •  10gen supported •  C, C# (.Net), C++, Erlang, Haskell, Java, JavaScript, Perl, PHP, Python, Ruby, Scala •  Community supported •  Clojure, ColdFusion, F#, Go, Groovy, Lua, R •  http://www.mongodb.org/display/DOCS/Overview+- +Writing+Drivers+and+Tools
23. 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
24. @mongodb   ©  Copyright  2010  10gen  Inc.   conferences,  appearances,  and  meetups   http://www.10gen.com/events     http://bit.ly/mongoQ     Facebook                    |                  Twitter                  |                  LinkedIn   http://linkd.in/joinmongo   download at mongodb.org We’re  Hiring  !   Engineers,  Sales,  Evangelist,  Marketing,  Support,  Developers    
25. •  Use cases •  Case studies Use cases and customers
26. Content Management
27. Gaming
28. Analytics
29. ©  Copyright  2010  10gen  Inc.   try at try.mongodb.org
30. @mongodb   ©  Copyright  2010  10gen  Inc.   conferences,  appearances,  and  meetups   http://www.10gen.com/events     http://bit.ly/mongoQ     Facebook                    |                  Twitter                  |                  LinkedIn   http://linkd.in/joinmongo   download at mongodb.org We’re  Hiring  !   sridhar@10gen.com   @snanjund