Real Time Analytics with

Vagmi Mudumbai@vagmi / @reducedata

What is Cassandra?

DynamoBased on

FacebookBuilt by

Key Value Storeis both a

Column Storeand a

The CAP Theorem

Column Families

HashMap<RowKey,SortedMap<ColumnName, Value>>

id name email country

1 Vagmi me@vagmim.in IN

2 Karthik yeskarthik@blah IN

3 MarkZ mark@fb US

Rowkey 1 2 3

name Vagmi Karthik MarkZ

email me@vagmim.in yeskarthik@blah mark@fb

country IN IN US

The Problem

As a user, I want to view real time metrics and filter by dimensions like time, city,

category, etc.

select sum(measure) from events where time between A and B and country=’US’ and

device_platform=’Android’

The wrong way

HashMap<RowKey,SortedMap<ColumnName, Value>>

Counters

create column family view_counts_hourly with comparator=UTF8Type and default_validation_class=CounterColumnType and key_validation_class=UTF8Type;

http://reducedata.com/, Chrome, 2014-03-14 15:30:00Z,

IP, Cookie-Info

RowKey 20140101 20140102 20140103 20140104 ... ... 20140628 ... 20150308

sid1#us 2553 2341 2342 3242 ... ... 32342 ... 33423

sid1#us#chrome 1556 1532 1892 ... ... ... ... ... ...

sid1#us#chrome#25 833 899 1200

Uniques?but what about

Bitmaps to the rescue

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

u1 u2 u3 u4 u5 u6 u7 u8 u9 u10 u11 u12 u13 ... ... ...

UID- 1328abc2838fd283e282

Fast Hash Function - Murmur32

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

u1 u2 u3 u4 u5 u6 u7 u8 u9 u10 u11 u12 u13 ... ... ...

RowKey 20140101 20140102 20140103 20140104 ... ... 20140628 ... 20150308

sid1#us 10101 10111 11100 11101 ... ... ... ... 11101

sid1#us#chrome ... ... ... ... ... ... ... ... ...

sid1#us#chrome#25 10101 11101 11100 …. ... ... ... ... ...

But I do not have Big Data

Oh andwe’re hiring

(vagmi@reducedata.co)

Thanks@vagmi on

Github / Twitter / Facebook