MongoDB quickstart for Java, PHP, and Python developers
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MongoDB Introduction for Java, Python and PHP Developers
Covers using MongoDB from a Java, PHP and Python developer’s perspective. Uses the Official MongoDB driver for Java, Python and PHP as well as command line tools for MongoDB to teach core concepts.
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Outline• Theory and Architecture of MongoDB (49%)• Setup instructions (9%)• Code examples in JavaScript, PHP, Python and Java
(39%)• 3% random
© 2012 10gen. MongoDB®, Mongo®, and theleaf logo are registered trademarks of 10gen, Inc.
10gen in no way endorses this slide deck or Mammatus Tehcnology Inc.
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MongoDB• NoSQL landscape full of contenders tackling big data
problems • MongoDB very capable • Document-oriented schema-less storage solution • JSON-style documents to represent, query and
modify data• Supports many clients/languages Python, PHP, Java,
Ruby, C++, etc.
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Resources• 10Gen site (http://www.mongodb.org)
– Great documentation and presentations
• InfoQ articles and presentations• Wikipedia• http://mongly.com/
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About Author• Rick Hightower, founder of ArcMind (RIP) and Mammatus,
father of five• Former CTO of LearningPatterns and Trivera Technologies
(global training and consulting firms)• Director of Development at 3 different places• Author of five technical books• Editor at InfoQ• 20 years hacking code (C, Python, C++, Java, etc.)• https://twitter.com/#!/RickHigh
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About Mammatus, ArcMind• ArcMind focused on Spring framework, JSF, Java EE,
Spring MVC, Grails, Groovy, Development, Tiles, etc.– Started in 2003 ended in 2009– Lot of clients (Boeing, Qualcomm, Bank of America, et.c), lots
of traveling
• Mammatus Tech (bumpy clouds) focuses on Cloud computing, NoSQL, BigData, Map Reduce, Java, PHP, Python, EC2, etc.– Started in 2009– http://cloud.mammatustech.com/
– http://nosql.mammatustech.com/
– http://www.mammatustech.com/
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Feedback welcome• Send any and all feedback to
• Criticism welcome– Prefer constructive criticism, but will take any and all– Needed for continuous improvement of this slide deck and my
knowledge
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Creative Commons• This slide deck and all material therein are covered
under creative commons• You can use all material in here as long as you don’t
copy it word for word and then use it for commercial reasons
• Other material in here from other sources are covered under fair use
• http://creativecommons.org/
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Why MongoDB?• MongoDB great active community• Supports: • High availability,• Journaling• Replication, • Sharding, • Indexing,• Aggregation,• Map/Reduce
MongoDB commercialhttp://www.10gen.com/what-is-mongodb
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MongoDB is a top job trend
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Leader in the NoSQL space?
MongoDB seems to bethe clear mind-share leader
Cassandra a close second
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Why do Developers pick Mongo?• NoSQL, in general, can be more agile than full
RDBMS/ SQL – problems with schema migration– a lot of upfront design needed for RDBMS– (or a lot schema migration later)
• MongoDB does not require a lot of ramp up time– Easy to get started– Many DevOps things come for free– Easy on ramp for NoSQL – Gateway drug?
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Why PHP, Python and Java?
Might add Ruby later to the mix or just focus on these
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Built for speed | Cache built in• MongoDB was built with speed in mind• Speed shaped architecture of MongoDB• Uses binary protocol instead of HTTP text/
(CouchDB)• Pads disk space around document
– faster updates– uses more disk
• Uses memory-mapped files as default storage engine, letting OS manage swapping– Linux/Windows/Solaris really good at virtual memory...
MongoDB builds on top of this
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Negatives of MongoDB• Indexes are not as flexible as
Oracle/MySQL/Postgres or other NoSQL solutions– Order of index matters, uses B-Trees, not very many options
like more mature solutions
• Realtime queries might not be as fast as Oracle/MySQL and other NoSQL solutions
• Good enough if queries are simple• Probably hits the sweet spot of 20/80 rule• Not as mature as RDBMS• Does not have full text search engine
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Very useful still• Every version seems to add more features• Added journaling so they can have single server
durability• Improved Replica’s with Replica Sets• Replica Sets and Autosharding required very little
admin once running• What it does, it does well...
– Can be combined with Relational database– Can be combined with full text search (Solr)– Can be combined with Hadoop
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• MTV• Craigslist• Disney• Shutterfly• foursqaure• bit.ly• The New York Times• Barclay’s• The Guardian
• SAP• Forbes• National Archives UK• Intuit• github• LexisNexis• many more
Who uses MongoDB?
Big names, big data
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MongoDB Concept• Oracle: Schema, Tables, Rows, Columns• MySQL: Database, Tables, Rows, Columns• MongoDB: Database, Collections, Document, Fields• MySQL/Oracle: Indexes• MongoDB: Indexes• MySQL/Oracle: Stored Procedures• MongoDB: Stored JavaScript• Oracle/MySQL: Database Schema• MongoDB: Schema free!
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MongoDB Architecture
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Additional Mongo Features• Geo Indexing: How close am I to X?• File Storage
– Stores large files and file meta-data• Capped Collection (like Ring Buffer)
– Older documents auto-deleted• Aggregation• Auto sharding• Load sharing for reads • High availability• Speed or durability (journaling)
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What do you need?• Read scalability and high availability (HA)?
– Use Replica Sets
• Write scalability?– Use Autosharding (also just called sharding)
• HA, Read Scalability, and Write Scalability?– Use Autosharding and Replica Sets
• You can start basic and add as your growth/needs change– Capacity planning, monitoring, determine needs
HA
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Durability• Journaling added in 1.8, and is now default for 64 bit
OS for MongoDB 2.0• Prior to that, you used replication to make sure copy
of operation was on replica– MongoDB did not have single server durability, now it does
with addition of journaling
• General thought was/is durability is overvalued• You can also force an fsync• See links in notes
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• Drivers know the primary• If primary down, Drivers
know how to get new primary
• Data is replicated after writing
• Typical to have three in a replica set
• You can do more• Load sharing for reads
Replica Sets
Replica 1 Replica 2
Replica 0PRIMARY
Client Driver
Read/WriteRead
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Replica Sets Usage• Business Continuity• Data Redundancy• High Availability• Load sharing (reads) • “Just works / NoOps (low ops)”
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Replica Sets• Non-blocking master/slave replication• Auto failover• Two or more nodes (usually three)• No primary, master is nominated• Share nothing architecture• Brains in the client libraries • Client libraries (Drivers) are Replica Set aware• Client can block until data is replicated on all servers
(for important data)
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Replica Sets• You only write to the master, it then replicates to
slaves• Replication is by default async (non-blocking)• Slave data and write data can be out of sync
– There are workarounds– You can force master to sync to master before
continuing (blocking, sync)• Sync blocking is slower• Async non-blocking is faster (eventual consistency)
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Durability and Replica Sets• Client libraries can do the following:
• Wait until write has happened on all replicas• Wait until write is on two servers (primary and one
other)• Wait until write has occurred on majority of replicas• Wait until write operation has been written to
journal
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Replica Sets• Replica Sets and Autosharding go hand in hand for
mass scale out• Replica Sets are good for failover and speeding up
reads, but...• To speed up writes, you need autosharding
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Sharding• Sharding allows MongoDB to scale horizontally • Sharding = partitioning• Auto-shards
– load balances – changes for data distribution
• Elastic adding of new nodes• Supports automatic failover (along with replica sets)• No single point of failure• 90% of deployments don’t need sharding according
to Roger Bodamer
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• Client Driver talks directly to mongod process
Non-sharded client connection
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• Three actors now: mongod, mongos, and Client Driver library
• Mongod is the process• Mongos is a router, it
routes writes to correct mongod instance
• Shares writing
Autosharded
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• Autosharding increases writes, helps with scale out
• Replica Sets are for high availability
• There is a whole lesson on sharding.
Autoshard plus Replica Set
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Sharding Topology• Config Servers (mongod)
– contain versioned shard topology– maps which shard has key– used by mongos– like DNS server for shards
• Mongos– Shard router clients drivers talk to Mongos instead of mongod
directly– Mongos uses Config Servers to find shard where key lives– MongoD are shards that can be replicated
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Large deployment
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MapReduce• Used for batch processing• Similar to Hadoop,• Massive aggregation possible through divide and
conquer• Used instead of Group/By in SQL
– Also added simplified framework to MongoDB (aggregation framework)
• Map and Reduce functions are written in JavaScript– Executed on server, code next to data it is operating on
• Can copy results to results collections
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MapReduce Theory
Image from http://code.google.com/p/mapreduce-framework/wiki/MapReduce
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Incremental MapReduce• Run MapReduce job over collections• Run a second job but only over new documents in
collection• Use reduce output to merge new data into existing
collection
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Aggregation Framework• Added in MongoDB 2.1• Similar to SQL group by• Before Aggregation framework, you had to use
MapReduce for things like SQL group by• Easier to use than MapReduce
Table from 10 Gen http://www.mongodb.org/display/DOCS/SQL+to+Aggregation+Framework+Mapping+Chart
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Aggregation Framework
Table from 10 Gen http://www.mongodb.org/display/DOCS/SQL+to+Aggregation+Framework+Mapping+Chart
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MongoDB versus SQL
Compare contrast
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SQL to Mongo
From http://www.mongodb.org/display/DOCS/SQL+to+Mongo+Mapping+Chart
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Mongo versus SQL
From http://www.mongodb.org/display/DOCS/SQL+to+Mongo+Mapping+Chart
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Mongo versus SQL
From http://www.mongodb.org/display/DOCS/SQL+to+Mongo+Mapping+Chart
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Mongo vs. SQL
From http://www.mongodb.org/display/DOCS/SQL+to+Mongo+Mapping+Chart
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Getting Started with Mongo
Installing and using Mongo
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Install (1 of 2)• http://www.mongodb.org/downloads• Extract
– ~/mongodb-platform-version/
• $ sudo mkdir /etc/mongodb/data• Create file
– /etc/mongodb/mongodb.config
• $ cat mongodb.config – dbpath=/etc/mongodb/data
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Install (2 of 2)• Link:• sudo ln -s ~/mongodb-platform-version/ /usr/local/mongodb
• Add to Path:• export PATH=$PATH:/usr/local/mongodb/bin
• Run the server:• mongod --config /etc/mongodb/mongodb.config
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Run the client (type db.version())• $ mongo• MongoDB shell version: 2.0.4• connecting to: test• …• > db.version()• 2.0.4• >
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Client: mongo db.help()• > db.help()• DB methods:• db.addUser(username, password[, readOnly=false])• db.auth(username, password)• db.cloneDatabase(fromhost)• db.commandHelp(name) returns the help for the command• db.copyDatabase(fromdb, todb, fromhost)• db.createCollection(name, { size : ..., capped : ..., max : ... } )• db.currentOp() displays the current operation in the db• db.dropDatabase()• db.eval(func, args) run code server-side• db.getCollection(cname) same as db['cname'] or db.cname• db.getCollectionNames()
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db.help()
db.getLastError() - just returns the err msg stringdb.getLastErrorObj() - return full status objectdb.getMongo() get the server connection objectdb.getMongo().setSlaveOk() allow this connection to read from the nonmaster member of a replica pair
db.getName()db.getPrevError()db.getProfilingStatus() - returns if profiling is on and slow threshold db.getReplicationInfo()db.getSiblingDB(name) get the db at the same server as this onedb.isMaster() check replica primary statusdb.killOp(opid) kills the current operation in the dbdb.listCommands() lists all the db commandsdb.logout()
db.printCollectionStats()db.printReplicationInfo()db.printSlaveReplicationInfo()db.printShardingStatus()db.removeUser(username)db.repairDatabase()db.resetError()db.runCommand(cmdObj) run a database command. if cmdObj is a string, turns it into { cmdObj : 1 }
db.serverStatus()db.setProfilingLevel(level,<slowms>) 0=off 1=slow 2=alldb.shutdownServer()db.stats()db.version() current version of the serverdb.getMongo().setSlaveOk() allow queries on a replication slave serverdb.fsyncLock() flush data to disk and lock server for backupsdb.fsyncUnock() unlocks server following a db.fsyncLock()
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Create Employee Collection• > use tutorial;• switched to db tutorial• > db.getCollectionNames();• [ ]• > db.employees.insert({name:'Rick
Hightower', gender:'m', gender:'m', phone:'520-555-1212', age:42});
• Mon Apr 23 23:50:24 [FileAllocator] allocating new datafile /etc/mongodb/data/tutorial.ns, filling with zeroes…
• ..
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Query DB (1 of 2)• > db.getCollectionNames();• [ "employees", "system.indexes" ]
• > db.employees.find()• { "_id" :
ObjectId("4f964d3000b5874e7a163895"), "name" : "Rick Hightower", "gender" : "m", "phone" : "520-555-1212", "age" : 42 }
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Query DB (2 of 2)• > db.employees.find({name:"Bob"})
• > db.employees.find({name:"Rick Hightower"})• { "_id" : ObjectId("4f964d3000b5874e7a163895"), "name" : "Rick Hightower", "gender" :
"m", "phone" : "520-555-1212", "age" : 42 }
• > db.employees.find({age:{$lt:100}})• { "_id" : ObjectId("4f964d3000b5874e7a163895"), "name" : "Rick Hightower", "gender" :
"m", "phone" : "520-555-1212", "age" : 42 }
• > db.employees.find({age:{$lt:100}})[0].name• Rick Hightower
• > db.system.indexes.find()• { "v" : 1, "key" : { "_id" : 1 }, "ns" : "tutorial.employees", "name" : "_id_" }
• > db.employees.find({_id : ObjectId("4f964d3000b5874e7a163895")})• { "_id" : ObjectId("4f964d3000b5874e7a163895"), "name" : "Rick Hightower", "gender" :
"m", "phone" : "520-555-1212", "age" : 42 }
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Java: Setup• Download latest mongo driver
– https://github.com/mongodb/mongo-java-driver/downloads
• $ mkdir tools/mongodb/lib• $ cp mongo-2.7.3.jar tools/mongodb/lib
• Create new Eclipse project in new Workspace
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Java: Setup Eclipse (1 of 2)
• Right Click Project, Open Properties, Java Build Path->Libraries->Add Variable->Configure Variable
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Java: Setup Eclipse (2 of 2)
• From Properties->Java Build Path->Libraries• Click Add Variable, Select MONGO, Click Extend…, select jar
file you just downloaded
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Java: Using Java Basics (1 of 2)
Out:{ "_id" : { "$oid" : "4f964d3000b5874e7a163895"} , "name" : "Rick Hightower" , "gender" : "m" , "phone" : "520-555-1212" , "age" : 42.0}{ "_id" : { "$oid" : "4f984cce72320612f8f432bb"} , "name" : "Diana Hightower" , "gender" : "f" , "phone" : "520-555-1212" , "age" : 30}
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Using Java Basics (2 of 2)
Output:Rick?{ "_id" : { "$oid" : "4f964d3000b5874e7a163895"} , "name" : "Rick Hightower" , "gender" : "m" , "phone" : "520-555-1212" , "age" : 42.0}Diana?{ "_id" : { "$oid" : "4f984cae72329d0ecd8716c8"} , "name" : "Diana Hightower" , "gender" : "m" , "phone" : "520-555-1212" , "age" : 30}Diana by object id?{ "_id" : { "$oid" : "4f984cce72320612f8f432bb"} , "name" : "Diana Hightower" , "gender" : "f" , "phone" : "520-555-1212" , "age" : 30}
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All of the above but in Python• Install mongodb lib for Python• MAC OSX• $ sudo env ARCHFLAGS='-arch i386 -arch x86_64'
python -m easy_install pymongo• Linux• $ easy_install pymongo• or• $ pip install pymongo
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Basic Python Operations (1 of 2)
Output:{u'gender': u'm', u'age': 42.0, u'_id': ObjectId('4f964d3000b5874e7a163895'), u'name': u'Rick Hightower', u'phone': u'520-555-1212'}{u'gender': u'm', u'age': 30, u'_id': ObjectId('4f984cae72329d0ecd8716c8'), u'name': u'Diana Hightower', u'phone': u'520-555-1212'}{u'gender': u'm', u'age': 8, u'_id': ObjectId('4f9e111980cbd54eea000000'), u'name': u'Lucas Hightower', u'phone': u'520-555-1212'}
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Basic Python Operations (2 of 2)
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All of the above but in PHP• Install on PHP• $ sudo pecl install mongo
• Add to php.ini:• extension=mongo.so
• Restart apache • $ apachectl stop• $ apachectl start
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Mongo PHP Basics (1 of 2)
Output:array ( '_id' => MongoId::__set_state(array( '$id' => '4f964d3000b5874e7a163895', )), 'name' => 'Rick Hightower', 'gender' => 'm', 'phone' => '520-555-1212', 'age' => 42, )
array ( '_id' => MongoId::__set_state(array( '$id' => '4f984cae72329d0ecd8716c8', )), 'name' => 'Diana Hightower', 'gender' => ‘f', 'phone' => '520-555-1212', 'age' => 30, )
array ( '_id' => MongoId::__set_state(array( '$id' => '4f9e170580cbd54f27000000', )), 'gender' => 'm', 'age' => 8, 'name' => 'Lucas Hightower', 'phone' => '520-555-1212', )
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Mongo PHP (2 of 2)
OutputRick? array ( '_id' => MongoId..., 'name' => 'Rick Hightower', 'gender' => 'm', 'phone' => '520-555-1212', 'age' => 42, )Diana? array ( '_id' => MongoId::..., 'name' => 'Diana Hightower', 'gender' => ‘f', 'phone' => '520-555-1212', 'age' => 30, )Diana by id? array ( '_id' => MongoId::..., 'name' => 'Diana Hightower', 'gender' => 'f', 'phone' => '520-555-1212', 'age' => 30, )
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Shell commands in action• > show dbs• local (empty)• tutorial 0.203125GB
• > show collections• employees• system.indexes
• > show users
• > show profile• db.system.profile is empty• Use db.setProfilingLevel(2) will enable profiling• ..
• > show logs• global
• > show log global• Mon Apr 23 23:33:14 [initandlisten] MongoDB starting : pid=11773 port=27017 dbpath=/etc/mongodb/data 64-bit…• …• Mon Apr 23 23:33:14 [initandlisten] options: { config: "/etc/mongodb/mongodb.config", dbpath: "/etc/mongodb/data" }
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Collection Methods (1 of 2)• > db.employees.help()• DBCollection help•
• db.employees.find().help() - show DBCursor help• db.employees.count()• db.employees.dataSize()• db.employees.distinct( key ) - eg. db.employees.distinct( 'x' )• db.employees.drop() drop the collection• db.employees.dropIndex(name)• db.employees.dropIndexes()• db.employees.ensureIndex(keypattern[,options]) - options is an object with these possible fields:
name, unique, dropDups• db.employees.reIndex()• db.employees.find([query],[fields]) - query is an optional query filter. fields is optional set of fields to
return. e.g. db.employees.find( {x:77} , {name:1, x:1} )• db.employees.find(...).count()• db.employees.find(...).limit(n)• db.employees.find(...).skip(n)• db.employees.find(...).sort(...)
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Collection Methods (2 of 2)
db.employees.findOne([query])db.employees.findAndModify( { update : ... , remove : bool [, query: {}, sort: {}, 'new': false] } )db.employees.getDB() get DB object associated with collectiondb.employees.getIndexes()db.employees.group( { key : ..., initial: ..., reduce : ...[, cond: ...] } )db.employees.mapReduce( mapFunction , reduceFunction , <optional params> )db.employees.remove(query)db.employees.renameCollection( newName , <dropTarget> ) renames the collection.db.employees.runCommand( name , <options> ) runs a db command with the given name where the first param is the collection name
db.employees.save(obj)db.employees.stats()db.employees.storageSize() - includes free space allocated to this collectiondb.employees.totalIndexSize() - size in bytes of all the indexesdb.employees.totalSize() - storage allocated for all data and indexesdb.employees.update(query, object[, upsert_bool, multi_bool])db.employees.validate( <full> ) – SLOWdb.employees.getShardVersion() - only for use with shardingdb.employees.getShardDistribution() - prints statistics about data distribution in the cluster
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Basic shell commands (1 of 2)• > help• db.help() help on db methods• db.mycoll.help() help on collection
methods• rs.help() help on replica set
methods• help admin administrative help• help connect connecting to a db help• help keys key shortcuts• help misc misc things to know• help mr mapreduce
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Basic shell commands (2 of 2)• > help• …• show dbs show database names• show collections show collections in current database• show users show users in current database• show profile show most recent system.profile entries time>=
1ms
• show logs show the accessible logger names• show log [name] prints out the last segment of log in memory, • use <db_name> set current database
• DBQuery.shellBatchSize = x set default number of items to display on shell
• exit quit the mongo shell
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Tips for scaling mongo• Roger Bodamer• http://www.infoq.com/presentations/Scaling-with-M
ongoDB• Good ideas on EC2 shortcoming• RAID configuration (RAID 10 for speed and scaling)• Config Servers know where keys are, has key to
shard mapping, mongos refer to config servers
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Tips for scaling mongo• Don’t use sharding unless needed• 90% of deployments don’t need sharding
according to Roger Bodamer– Are you Twitter, Linkedin, Facebook, Foursquare? No– You probably not going to need it
• Replica Sets are more needed– Why? HA, read scalability
• Mongos can live on primary box• ConfigServer can live on a primary box• http://www.infoq.com/presentations/Scaling-with-MongoDB
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Tips for scaling mongo• Replicas should be on separate boxes
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Backups• You can use tools with mongodb• Or, if your hardware supports shutdowns• Sync to disk, shutdown cleanly, take a snapshot• http://www.infoq.com/presentations/Scaling-with-MongoDB
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Coming up• Basic CRUD and queries: Slide deck showing a simple CRUD listing
website in Python, Java and PHP using MySQL and MongoDB– Justing showing general operations
• Queries: Slide deck improving demo app to do more complex queries
• Replica Set: Slide deck setting up simple Replica Set in Amazon EC2 with boto scripts– Durability modes with examples in Python, PHP and Java
• Sharding: Slide deck setting up Sharding in MongoDB– Python, PHP and Java
• Map Reduce: Slide deck using sample app to do map reduce in Java, PHP and Python
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More to come• This is an early version of this.... expect updates• Looking for some feedback• Want to grow it out, put it on github, etc.• Do some compare and contrast between MongoDB,
MySQL, Cassandra, etc.• Things you won’t get from a vendor
– complaining– criticism– shortcomings