CASSANDRAWEB-SCALE NOSQL DATA PLATFORM

/ Marko Švaljek @msvaljek

0

ABOUT MESoftware Developer at KapschZagreb Cassandra Meetup

NUMBERS25% of the Fortune 100 use itApple - 75 000 nodes, 10 PB of dataNetflix - 2500 nodes, 1 trillion req/dayDataStax - professional Cassandra supportMeetup - 167 Groups, 114 Cities, 41 Countries

FUN PART

Android TV Box

Arduino

FUN PART

Android TV Box

Arduino

BREWER'S CAP THEOREMAvailability

Partition ToleranceConsistency

CA AP

CP

nodes can fail

same data for all network fails

RDBMS Cassandra

MongoDB

CONSISTENT HASHING - 1hash_function: row_key -> [0 .. 99]

A

BC

D0

25

50

75

CONSISTENT HASHING - 2Murmur3: row_key -> -263 to 263-1

A

B C

D

hash(C")

hash(A")

hash(D")

hash(B")

CONSISTENT HASHING - 3num_tokens: 256

virtual nodes

GOSSIPA

C

D

H B

F

E is down

G is down

12

3

CLIENT REQUESTSA

C

BDClient

CoordinatorNode

quorum =replication_factor

2+ 1

WRITE PATH

Memory

Disk

Commit log

memtable

Data

SSTable

memtableFlush

Inde

x

COMPACTION

Removetombstones

- - - - - - - - - -

- - - - - - - - - -

- - - - - - - - - -

Merge

Uncompacted data

- - - - -

- - - - -

- - - - -

Latest data entries

- - - - -

- - - - -

- - - - -

Compacted data

Consolidate

BLOOM FILTER

1 1 1 0 1 1 0 0 0 1 0 1

A B C

D

✓ ✓ ✗

READING FROM SSTABLEData?

Memory

Disk

Read Bloom Filter

Key Cache

DataSSTable

Data not in filter Data is in filter

DATA ORGANIZATIONKeyspace

Column family (table)

Row ...Column Column

Timpestamp Timpestamp

Value Value

KEYSPACECREATE KEYSPACE used_cars WITH replication = { 'class': 'SimpleStrategy', 'replication_factor' : 1};

CREATE KEYSPACE used_cars WITH replication = { 'class': 'NetworkTopologyStrategy', 'DC1' : 1, 'DC2' : 3};

TABLESCREATE TABLE users ( username text PRIMARY KEY, password text, first_name text, last_name text, state text);

INSERTINGINSERT INTO offers (username, date, price, brand, model, year, mileage, color) VALUES ('jsmith', '2014-09-19 11:35:20', 6000, 'BMW', '120i', 2010, 40000, 'Black');

UPDATEUPDATE offers SET brand = 'Ford', model = 'Mustang' WHERE username = 'jdoe' AND date = '2014-08-11 17:12:32+0200';

Use upsert (insert same data) when possibleNO updating of primary key fields

DELETEDELETE FROM offers WHERE username = 'jdoe' AND date = '2014-08-11 17:12:32+0200';

tombstones

SELECTSELECT username, date, brand, model FROM offers WHERE username = 'jsmith';

username | date | brand | model----------+--------------------------+-------+------- jsmith | 2014-05-11 01:22:11+0200 | Ford | Orion jsmith | 2014-09-09 11:35:20+0200 | BMW | 118d jsmith | 2014-09-19 11:35:20+0200 | BMW | 120i jsmith | 2014-09-20 17:12:32+0200 | Audi | A6

APPS15+ languages supported

var cql = require('node-cassandra-cql');

var client = new cql.Client({ hosts: ['127.0.0.1:9042'], keyspace: 'test'});

client.execute('SELECT * FROM test_table', [], function(err, result) { for (var i = 0; i < result.rows.length; i++) { console.log(result.rows[i].get('id')); console.log(result.rows[i].get('test_value')); } });

THANK YOU!

Q & A

@msvaljek