What's New in the PHP Driver

Hannes Magnusson, [email protected]

@bjoriNovember 15th, 2012

What’s new in thePHP Driver (1.3.0)

Thursday, 15 November 12

mailto:[email protected]


• Hannes / @bjori• Icelandic

– Oslo, Norway– London, England– San Francisco, USA

• PHP Contributor • PHP Driver Engineer

» @10gen

About me

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Agenda

• Removed not-so-cool stuff• New cool stuff

• Connection handling / Replica Sets– Write Concerns– Read Preferences


Removed stuff


Pooling

• Bye bye!• MongoPool::*()• Mongo->poolDebug();• Mongo->get/setPoolSize();

– Replaced by one persistent connection per• host:port;replicaSetName;credentials;pid combo

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Deprecated

• Mongo->connectUtil()• Mongo->get/setSlaveOkay()• Mongo->last/prev/reset/forceError()• Mongo->switchSlave()

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New stuff


MongoClient !!

• Acknowledged writes by default! \o/\o/• No deprecated methods

– Old Mongo class now extends MongoClient and adds back the old behaviour and methods

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• $mongoCollection->aggregate()• $mongoCollection->findAndModify()• TTL Collections

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$mongoCollection->ensureIndex( array("dateField" => 1), array("expireAfterSeconds" => 3600));


Aggregation Framework

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$ops = array( array( '$project' => array( "author" => 1, "tags" => 1, ) ), array('$unwind' => '$tags'), array( '$group' => array( "_id" => array("tags" => '$tags'), "authors" => array('$addToSet' => '$author'), ), ),);$results = $collection->aggregate($ops);


New cool stuff

• ReadPreferences• WriteConcerns• Connection handling

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What does the driver do?

Its responsibilitiesConnection handling/failover


The Driver

• Full C level client library, no external dependencies– Connection handling– Memory usage reported by PHP (almost)– Connection handling– MongoDB Wire protocol (OP_[CRUD], KILL_CURSOR)– Connection handling– Authentication– Connection handling

• BSON serialization• Connection handling• Command wrappers/helpers• Connection handling

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Replica Sets

Establishing connections


Replica Set – Configuration Options

> conf = { _id : "mySet", members : [ {_id : 0, host : "Node1”, tags : {"dc": "us"}}, {_id : 1, host : "Node2", priority : 20, tags : {"dc": "is"}}, {_id : 2, host : "Node3”, priority : 30, tags : {"dc": "is"}}, {_id : 3, host : "Node4", hidden : true}, {_id : 4, host : "Node5", hidden : true, slaveDelay : 3600} ]}

> rs.initiate(conf)




> rs.initiate(conf)

Primary DC




> rs.initiate(conf)

Secondary DCDefault priority = 1




> rs.initiate(conf)

Analytics node




> rs.initiate(conf)

Backup node


Replica Set - Creation

Node 1 Node 2

Node 3Node 4 Node 5


Replica Set - Initialize

Node 1 Node 2

Node 3

RS Init

Node 4 Node 5


Replica Set - Initializing

Node 1 Node 2

Node 3

HeartbeatElection

Node 4 Node 5


Replica Set - Initialized

Node 1Secondary

Node 2Secondary

Node 3Primary

Node 4(hidden)

Node 5(hidden)


Replica Set - Driver view

Node 1Secondary

Node 2Secondary

Node 3Primary

Driver


Connecting to Replica Set

• Connect to Node1– send `ismaster` then `ping`

• Connect to Node3...• Topology discovery

– Match hostnames & Replica Set names

– Verify the seedlist

– Discover more nodes

– Connect to Node2...26

<?php$servers = "mongodb://Node1,Node3";$options = array( "replicaSet" => "mySet",);$m = new MongoClient($servers, $options);?>


Connections

• Each unique connection string• host:port;replicaSetName;user/pass/db;pid

• Once per process• Closed & Cleaned up during shutdown

– Please don’t close connections manually :)

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Read Preference

Secondary readsPrioritise servers / datacenters


Replica Set - Default only primary

Node 1Secondary

Node 2Secondary

Node 3Primary

Driver


Read Preferences

• Only read from primary• Read from secondaries• Read from specific secondaries• Only read from secondaries when primary

down• Don’t care, just the nearest one• Preferably node with a given tag

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Read Preferences

• Modes (readPreference)– primary, primaryPreferred– secondary, secondaryPreferred– nearest

• Tag Sets (readPreferenceTags)– Uses Replica Set tags– Passed Tag is used to find matching members

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Detecting failures / failovers

• Runs `ping` every 5 seconds (mongo.ping_interval)

• Runs `ismaster` every 60 seconds (mongo.is_master_interval)

• Server/connection failure/force close– rs.stepDown()– service mongod stop– Query failure– ...

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Read Preference +

Failovers

No primary available


Replica Set - all well

Node 1Secondary

Node 2Secondary

Node 3Primary

Driver


Replica Set

Node 1Secondary

Node 2Secondary

Node 3Primary

Driver


Read Preferences

<?php$servers = "mongodb://Node1,Node2,Node3";$options = array( "replicaSet" => "mySet", "readPreference" => "primaryPreferred", "readPreferenceTagS" => "dc:is",);$m = new MongoClient($servers, $options);?>

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• Read from Primary if available• Otherwise from a secondary in Iceland


WriteConcerns

How much do you love your data?(not actually new, but still cool)


Write Preference

• Unacknowledged (w=0)• Acknowledged (w=1) • Wait for replication (w=2+)• Wait for replication to tagset (w=string) • Wait for journal sync (j=1)


Write Preference

<?php

$examples = $mongo->test->example;$data = array("Hello" => "World");$examples->insert($data, array("w" => 2));$examples->insert($data, array("w" => "is"));

?>

• w=majority• (replicate to the majority of the RS)


New Connection handlingRead Preferences

Acknowledged writes by default

RC2 released last Monday...RC3 this coming Monday...Final .. 2weeks?


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What's New in the PHP Driver

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