What's New in the PHP Driver

What’s new in the
PHP Driver (1.3.0)

Hannes Magnusson, 10gen
bjori@10gen.com
@bjori
November 15th, 2012

Thursday, 15 November 12

About me

• Hannes / @bjori
• Icelandic
– Oslo, Norway
– London, England
– San Francisco, USA
• PHP Contributor
• PHP Driver Engineer
» @10gen
3


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

6


Deprecated

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

7


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

9


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

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

10


Aggregation Framework

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

11


New cool stuff

• ReadPreferences
• WriteConcerns
• Connection handling

12


What does the driver do?

Its responsibilities
Connection handling/failover


The Driver

• Full C level client library, no external dependencies
– Connection handling
– Memory usage reported by PHP (almost)
– MongoDB Wire protocol (OP_[CRUD], KILL_CURSOR)
– Authentication
• BSON serialization
• Command wrappers/helpers
14


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)



> conf = {
_id : "mySet", Primary DC

members : [
]
}

> rs.initiate(conf)



> conf = {
Secondary DC
_id : "mySet",
Default priority = 1
members : [
]
}

> rs.initiate(conf)



> conf = {
_id : "mySet", Analytics node
members : [
]
}

> rs.initiate(conf)



> conf = {
_id : "mySet",
members : [
]
}
Backup node

> rs.initiate(conf)


Replica Set - Creation

Node 1 Node 2

Node 4 Node 3 Node 5


Replica Set - Initialize

RS Init

Node 1 Node 2



Replica Set - Initializing

Node 1 Node 2
Heartbeat
Election



Replica Set - Initialized

Node 1 Node 2
Secondary Secondary

(hidden) Primary (hidden)


Replica Set - Driver view

Driver

Node 1 Node 2
Secondary Secondary

Node 3
Primary


Connecting to Replica Set

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

• 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


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 :)

27


Read Preference

Secondary reads
Prioritise servers / datacenters


Replica Set - Default only primary

Driver

Node 1 Node 2
Secondary Secondary

Node 3
Primary


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

30


Read Preferences

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

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

31


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
– ...

32


Read Preference
+
Failovers

No primary available


Replica Set - all well

Driver

Node 1 Node 2
Secondary Secondary

Node 3
Primary


Replica Set

Driver

Node 1 Node 2
Secondary Secondary

Node 3
Primary


Read Preferences

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

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

36


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 handling
Read Preferences
Acknowledged writes by default

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


download at mongodb.org
We’re Hiring !
bjori@10gen.com @bjori

conferences, appearances, and meetups
http://www.10gen.com/events

Facebook | Twitter | LinkedIn
http://bit.ly/mongofb @mongodb http://linkd.in/joinmongo


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