Non-Relational Databases

Non-Relational DatabasesSan Francisco Perl MongersKristina ChodorowSeptember 3, 2009

Who am I?Software Engineer at 10genPerl, PHP, Java drivers

Technique #1: literally scale(Courtesy of Ask Bjorn Hansen)$3,200$4,000,000x 1250 =

Technique #2: shardnow-yesterdayyesterday-the day beforethe day before-the day before that

Technique #3: master-slave replicationRWWR/W?WR

CassandraDesigned by FacebookDistributed - eventually consistentColumn-oriented

CassandraWrites ALWAYS workTwo types of reads: high performanceguaranteed correctR/W atomic within column family

CassandraRow-oriented: joe, 34, karen, 25, bob, 50Column-oriented:joe, karen, bob, 34, 25, 50

Project VoldemortKey/value storeAutomatic replication/partitioning75 Github forks“It is basically a just a big, distributed, persistent, fault-tolerant hash table.”

Tokyo CabinetAnother key/value storeBlazing fast… theoreticallyLua for server-side scripting

Tokyo CabinetKey/value pairsArray storeIndex-able Hash{ name : “Chris” age : 27, DOB : “January 1”}

CouchDBMaster-Master ReplicationMap/ReduceREST API

MongoDBEase of useScalableDynamic queries - similar “feel” to SQLSpeed of key/value stores (almost)Power of RDBMSs (almost)

The Perl DriverAvailable at Github: www.github.com/mongodb/mongo-perl-driver/Install the Perl driver $ perl Makefile.PL && sudo make installAvailable on CPAN (but old):http://search.cpan.org/~flora/MongoDB-0.01/

Downloading MongoDBwww.mongodb.orgBinaries available for Linux, Mac, Windows, Solaris

Start the DB Server$ mkdir ~/db$$ tar zxvfmongodb-<OS>-1.0.0.tgz$ cdmongodb-<OS>-1.0.0$ bin/mongod --dbpath ~/db

Connecting to the Databaseuse MongoDB;my $connection = MongoDB::Connection->new;my $db = $connection->get_database(‘test’);my $collection = $db->get_collection(‘foo’);

Insertingmy $id = $collection->insert( { title => ‘My first blog post’, author => ‘Joe’, content => ‘Hello, world!’ comments => [] });

MongoDB::OIDan autogenerated primary keymy $id = $collection->insert({whatever});print Dumper($id);--------------------------------------------$VAR1 = bless( { 'value' => '4a9700dba5f9107c5cbc9a9c' }, 'MongoDB::OID' )

Updating$collection->update({_id => $id}, {‘$push’ => {comments => { ‘author’ => ‘Fred’, ‘comment’ => ‘Dumb post.” }}});

…which gives us:print Dumper($collection->find_one());--------------------------------------------{ title : ‘My first blog post’, author : ‘Joe’, content : ‘Hello, world!’ comments : [{ ‘author’ : ‘Fred’, ‘comment’ : ‘Dumb post’ }]}

Magic (not the Perl kind)$gt, $gte, $lt, $lte, $eq, $neq, $exists, $set, $mod, $where, $in, $nin, $inc$push, $pull, $pop, $pushAll, $popAll$c->query({ x => {‘$gt’ => 4}})

Queryingmy $commented_by_fred = $collection->query({ “comments.author” : “Fred” });my $commented_by_fred = $collection->query({ “comments.author” : qr/fred/i });

$where$collection->find_one({‘$where’ : ‘this.y == (this.x + this.z)’});Will work:{x => 1, y => 4, z => 3}{x => “hi”, y => “hibye”, z => “bye”}Won’t work:{x => 1, y => 1}

Optimizing $where$collection->find_one({ ‘name’ => ‘Sally’, ‘age’ => {‘$gt’ => 18}, ‘$where’ => ‘Array.sort(this.interests)[2] == “volleyball”’});

Speaking of indexing…$collection->ensure_index({“age” => “ascending”});$collection->ensure_index({ “name” => “descending”, “ts” => “descending”, “comments.author” => “ascending”});

Cursorsmy $cursor = $coll->query({“foo” => “bar”});my $obj;while (my $obj = $cursor->next) { ...}my @all = $cursor->all;

Pagingmy $cursor = $coll->query-> sort({ts => -1})-> skip($page_num * $results_per_page)-> limit($results_per_page);my @page = $cursor->all;

Logginginsert/update/remove is fastCapped collectionsSchemaless$inc for counts

Thank you!kristina@10gen.com@kchodorow@mongodbirc.freenode.net#mongodbwww.mongodb.org

Non-Relational Databases

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Non-Relational Databases