Silicon Valley Code Camp: 2011 Introduction to MongoDB
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This document provides an introduction and overview of MongoDB, a document-oriented NoSQL database. It discusses how MongoDB differs from relational databases, its support for schemaless documents and easy querying. Key concepts covered include collections, documents, inserting and querying data, and replication and scaling architectures like master-slave and replica sets. The document also touches on accessing MongoDB programmatically, object-document mappers, internal architecture details, administration, and comparisons to other NoSQL solutions.
Silicon Valley Code Camp: 2011 Introduction to MongoDB
- 1. Introduction to MongoDB Silicon Valley Code Camp Oct 8th, 2011
- 2. Before we start……NoSQL is a movement, its not antiSQLRelational Databases have their place, but they are not the only solutionDiversify - Best tool for the jobThe footers contain quotes from the video Mongo DB is Web Scale
- 3. AgendaRelational Databases vs. NoSQLCAP Theorem MongoDB at a high levelCollections, DocumentsInserting, Querying and UpdatingOther MongoDB CommandsReplication TopologiesUsing MongoDB via a driverFew InternalsAdministration
- 4. Relational DatabasesHave been around for yearsDe-facto standard for any persistence ACID compliantRigid SchemaUsually hard to scale over a distributed network Normalization is almost always a requirementORMs tend to limit the optimizations you can do to the queries.Relational Databases were'nt built for Web Scale. They have impotence mismatch.
- 5. NoSQLWhy?Not everything can be modeled in a relational constructCluster-aware out of the box. Replication, shardingetc. is built into the coreSchemaless(Mostly) Open Source, Community supportedHigh performance by design and not ball-and-chained with ACID
- 6. CAP Theorem : Pick TwoConsistency – Each client sees the same dataAvailability – The system is always available for any reads and writesPartition Tolerance – The system can tolerate any communication failure across the network (except someone pulling the plug across the datacenters).At any given point in time, only two of the above hold true in any distributed datastore.If thats what they need to do to get those kick ass benchmarks, then its a great design.
- 7. Visual Guide to NoSQL DatabasesSource: http://blog.nahurst.com/visual-guide-to-nosql-systems
- 8. How do they make up?Usually the NoSQL databases are AP, or CP.Consistency Eventually consistentWrite concernsAvailabilityRead-only stale data
- 9. MongoDB : High LevelDocument-based DatabaseSchemalessCluster-awareEasy Querying/Javascript SupportMemory MappedDrivers in all the popular languagesExcellent developer velocity (Supported by 10gen)Durable via JournalingC-P System based on the CAP theoremMongoDB handles WebScale. You turn it on and it scales right up.
- 10. CollectionsThe closest comparison to a MongoDB Collection in the relational world is a TableA collection is not bound by a schemaA collection has a namespaceCan be a capped collectionIt contains BSON documents
- 11. DocumentsClosest comparison in the relational world is a Row in a Table.Must reside within a CollectionLooks like (structured) JSON, stored as BSON within a collectionLimited to 16MB (as of 2.0)Larger sizes supported via GridFSReference : http://www.bsonspec.org. Defined as Binary-encoded Serialization format for JSON-like Documents.
- 12. Inserting DocumentsConsole defaults to localhost port 27017show databasesshow collectionsInsert a document in a collectionBulk inserts via Javascript
- 13. Querying and Updating DocumentsQuery a documentSelect certain fieldsUsing limit, skip, sort and countUsing explainIn Place Updates$inc, $push, $pull, $pop, $slice, $in, $ninIndexing on fieldsMongoDB is a Document Database, that does not need joins. It uses Map Reduce.
- 15. Replication: Master Slave Achieved by “declaring” 1 node as the master, and “declaring” many nodes as its slavesSingle point of failure/No failoverCan add any number of slaves easilyMay need to put slaves behind a load balancer
- 16. Replication : ReplicaSetsAchieved by creating a cluster, called a replSet, and adding “members” to it.The “primary” and “secondary” roles are decided among the nodes. There is no permanent “master” or “slave”.Automatic Failover via votingArbiter may be needed if there are even number of nodes to break a tieEasy to add new membersAdding load-balancing will void failover
- 17. Accessing MongoDBProgramaticallyScalaUsing casbahCode to insert a documentCode to find/queryCode to update
- 18. Object-Document MappersMongo Drivers understand Hashes, or DBObjects. A DBObject essentially is a MapThe class needs to be converted to a DBObject, either by the developer or by the driver.Some such mappers also provide a DAO which makes it easy to perform CRUD operations.MongoMapper for RubySalat for ScalaMorphia for Java
- 19. InternalsData is memory mapped, so writes can scale as no disk IO is performed with every write.Delayed writes to the disc, default 60 seconds.Always easier to keep the indices and the working set of the data in the memory to avoid swappingPre-allocated files in incrementsSmart algorithm to add padding to the storage when the document sizes are inconsistentDurability is achieved by journaling, introduced in 1.7
- 20. Replication InternalsThe almighty Oplog – Capped CollectionActs like a tx log which the slaves or secondaries read from and apply.getmore on the primary/master every 4sFailover and votingDelayed syncUsing rs.slaveOk() to query the secondaries in a replSet
- 21. Scaling MongoDBBe smart with your schema designKnow ahead of time if the system will be read-heavy or write-heavyUse explain(), use indicesDo not fetch the entire document - select fields.Keep an eye on index misses and page faults via mongostatDenormalize- avoid links, use embeds.You can never replicate enoughHorizontal scaling via shardingIf /dev/null is faster then WebScale, I’ll use it. Does /dev/null support sharding?
- 22. BackupsLock the database for a cold backupUse filer snapshotsUse mongodump -> BSON, mongorestore to restoreUse mongoexport -> JSON, mongoimport to restoreSpare slaves always help
- 23. MonitoringMMSDeveloped by 10genMuninPlugins available to monitor MongoDB ServerNagiosFor Machine Health Check
- 24. Comparison of NoSQL SolutionsSource: http://perfectmarket.com/blog/not_only_nosql_review_solution_evaluation_guide_chart
- 25. We’re hiring!corp.ign.com/careers, and @ignjobsScalaJavaPHP/ZendRailsElasticSearchMongoDBMySQLHTML5Jquery MobileSencha TouchPhonegapWordpressActionScript/FlashRedis/MemcachedCI/CD
- 26. AboutManish Pandit Sr. Engineering Manager IGN Entertainmenthttp://linkedin.com/in/mpandit@lobster1234