1.
Slide 1
HBase Vs Cassandra Vs
MongoDB - choose the right
NoSQL database
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2.
Slide 2
Objectives of this Session
• Un
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 Traditional databases
 Challenges with traditional databases
 CAP Theorem
 NoSQL to the rescue
 A BASE system
 Choose the right NoSQL database
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3.
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RDBMS/OLTP/Real Time
NoSQL/New SQL/BigData
DSS/OLAP/DW
Oracle
MySQL
MS SQL
DB2
Netezza
SAP Hana
Oracle Express
MongoDB
HBase
Cassandra
CouchDB
Database Categories
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4.
Slide 4 www.edureka.in
5000 TPS
Caching Layer
300 ~ 500 SQL
Transaction
100 ~ 200 SQL
Transaction
1000 TPS
WEB APPLICATION
RDBMS1
Applications Changing Data
RDBMS1
Elastic Scale
A Traditional database solution

5.
Slide 5 www.edureka.in
1000 TPS
Elastic Scale WEB APPLICATION
Applications Changing Data
Elastic Scale
CASSANDRA
300 ~ 500 SQL
Transaction
100 ~ 200 SQL
Transaction
5000 TPS
A NoSQL database solution

6.
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Challenges with traditional databases
 Not a good fit for large Data Volume (petabytes of data) with Varying data types
e.g. images, videos, text etc.
 Can’t scale for large data volume e.g. 15 - 20 petabyte data in Govt. of India
“AADHAR” project
 Scale-up - Limited by Memory and Processing (CPU) capabilities
 Scale-out - Cache dependent ‘Read’ and ‘Write’ Operations
 Complex RDBMS model – Parsing, Locking, Logging, Buffer pool, Threads etc.
 Sharding causes operational problems e.g. managing a shard failure
 Consistency – A bottleneck for Scalability in RDBMS
 Satisfying ACID is an hindrance for Scaling
 Relaxed consistency to scale out with NoSQL databases

7.
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CAP
We must understand the CAP
theorem when we talk about
NoSQL databases or in fact
when designing any distributed
system.
CAP theorem states that there are 3 basic requirements which exist in a special relation when designing
applications for a distributed architecture.
Consistency
Availability
Partition
Tolerance
CAP Theorem
This means that the system is always on (service guarantee
availability), no downtime.
This means that the system continues to function even the
communication among the servers is unreliable, i.e. the servers
may be partitioned into multiple groups that cannot communicate
with one another.
This means that the data in the database remains consistent after
the execution of an operation. For example after an update
operation all clients see the same data.

8.
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 CAP provides the basic requirements for a distributed system
to follow 2 of the 3 requirements.
 In theoretically it is impossible to fulfill all 3 requirements.
 Therefore all the current NoSQL database follow the different
combinations of the C, A, P from the CAP theorem.
CAP Theorem and NoSQL databases
 CA - Single site cluster, therefore all nodes are always
in contact. When a partition occurs, the system blocks.
 CP - Some data may not be accessible, but the rest is
still consistent/accurate.
 AP - System is still available under partitioning, but
some of the data returned may be inaccurate.
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9.
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NoSQL to the rescue
 A scale-out, shared-nothing architecture, capable of running on a large number of
nodes
 A non-locking concurrency control mechanism so real-time reads will not conflict
with writes
 Scalable replication and distribution
 Thousands of machines with distributed data
 An architecture providing much higher per-node performance than available from
the traditional SQL-based databases
 Schema-less Data Model
 Mostly Query and Few Updates

10.
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 Basically Available indicates that the system does guarantee availability, in terms of
the CAP theorem.
Basically Available
 Soft State indicates that the state of the system may change over time, even without
input. This is because of the eventual consistency model.
Soft State
 Eventual Consistency indicates that the system will become consistent over time,
given that the system doesn't receive input during that time.
Eventual Consistency
A BASE system gives up on consistency.
NoSQL database - A BASE not ACID system

11.
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~ 150 No SQL Database
are there in Market
~150
NoSQL database – Not a Panacea

12.
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NoSQL Database – Storage Architecture
CouchDB, MongoDB
Collection of key value
Connections
Incomplete Data
Tolerant
Query Performance, No
Standard Query Syntax
Hbase, Cassandra
Column Families
Fast Look-ups
Very Low Level API
Amazon Simple DB,
Redis
Collection of Key
Value pairs
Fast Look-ups
Stored Data
has no Schema
InfoGrid, Infinite Graph
“Property Graph” - Nodes
Graph Algorithms – Shortest
Path, Connected ness, Etc
Not easy to Cluster, traverse
whole graph to get answer
Data Model
Example
Weakness
Strength
Data Model
Example
Weakness
Strength
Data Model
Example
Weakness
Strength
Data Model
Example
Weakness
Strength
Document Data
Store Databases
Key Value
Databases
Columnar NoSQL
Databases
Graph NoSQL
Databases
No SQL
Database Types
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13.
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Right Data Model
Pros and Cons of
Consistency
Compromising
Features of RDBMS
Step 2
Step 3
Selecting a NoSQL database
Step 1
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14.
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Where to Use Cassandra?
 If looking for simple setup, maintenance and code
 Very High Velocity Random Reads & Writes
 Flexible Sparse / Wide Column Requirements
 No Multiple Secondary Index Needs
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15.
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Massive Scale, High Availability
Cassandra Use Case - Twitter

16.
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Where NOT to Use Cassandra?
Do not use Cassandra if your application has:
 Secondary Indexes.
 Relational Data.
 Transactional (Rollback, Commit)
 Primary & Financial Records.
 Stringent Security & Authorization Needs On Data
 Dynamic Queries on Columns.
 Searching Column Data
 Low Latency
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17.
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Where to Use HBase
 Optimized for reads
 Well suited for doing Range based scans
 Applications with strict consistency requirements
 Applications with fast read and writes with scalability
 Facebook uses it to manage its user statuses, photos, chat messages etc.
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18.
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Consistency and Scale
HBase Use Case - Facebook Messenger

19.
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 It is not optimized for classic transactional applications or even relational analytics
 Application that need:
 full table scans
 data to be aggregated, rolled up, analysed across rows
Where Not to use HBase

20.
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Where to Use MongoDB
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 RDBMS replacement for Web Applications
 Semi-structured Content Management
 Real-time Analytics & High-Speed Logging
 Caching and High Scalability
 Web 2.0, Media, SAAS, Gaming
http://www.mongodb.org/about/production-deployments/

21.
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 MySQL for Active posts
 MongoDB for Archived posts
 Migrated Two billion plus posts to MongoDB
 Migrated from RDBMS to MongoDB
 Storage of venues and check-ins
High-performance and Schema-free
MongoDB Use Cases

22.
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 Highly Transactional Applications
 Applications with traditional database systems requirements such as foreign-key
constraints etc.
Where Not to use MongoDB

23.
Slide 23 www.edureka.in
 Distributed and
scalable big data store
 Strong consistency
 Built on top of Hadoop
Distributed File
system (HDFS)
 CP on CAP
Cassandra MongoDBHBase
 High availability
 Incremental scalability
 Eventually consistent
 Trade-offs between
consistency and latency
 Minimal administration
 No SPF (Single Point of Failure)
 AP on CAP
 Schemas to change as applications
evolve (Schema-free)
 Full Index Support for High
Performance.
 Replication and Failover for High
Availability.
 Auto Sharding for Easy Scalability.
 Rich Document based queries for
Easy readability
 CP on CAP
HBase Vs Cassandra Vs MongoDB

24.
Slide 24
Questions?
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