Presented By

Tackling Single Node Failure in

Distributed Database System

Marzia Ahmed

Roll: 090232

Nazmul Hossain Bilash

Roll: 090236

Outlines

Introduction

How Existing Algorithm Works ??

Problems of Existing Algorithms

Thesis Objectives

Experiment and Result Analysis

Conclusion

References

How Proposed System Works??

Introduction

What is Database ?

Figure 1: General Block Diagram of Database

Introduction (Cont…)

Types of Database :

1. Centralized Database

Figure 2: Centralized Database

Continue…

2. Distributed Database

Figure 3: Distributed Database

Continue…

What is DBMS ?

A software that manages the DDB.

Provides an access mechanism.

Makes this distribution transparent to the users

A transparent system “hides” the implementation details

from the users.

Continue…

Figure 4: Structural view of DDBMS to users and Programmer

How Existing Algorithm Works??

What is Gossiping?

I know something, I am sitting next to Ali, and I tell him

(Now 2 of us “know”).

Later, he tells Jasmine and I tell Jannat

(Now 4 of us know).

Gossiping Algorithm

Describe steps about forwarded information.

Simple and easy to implement.

It refers –

Exchange mechanism

Network components- source of information.

Capable of information transfer.

Gossip-based Algorithm-

Randomized Algorithm

Perfect Knowledge Algorithm

Virtual Tree Algorithm

Randomized Algorithm (RA)

Nodes are selected randomly.

Data Redundancy.

Figure 5: Randomized algorithm redundancy example

Perfect Knowledge Algorithm (PKA)

Dynamically updated from the update status.

Figure 6: Propagating information in a network

Continue….

Figure 7: Node update process in case of perfect knowledge algorithm

Virtual Tree Algorithm (VTA)

Creates Graph structure which forms real world

networks.

Reliable & efficient mechanism for data transmission.

Used for –

Data aggregation

Resource allocation.

Propagating information

Reduce redundant transmission

Continue…..

Figure 8 : Communication path for the network of 32 nodes

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Figure 9 : Steps of the Update Propagation

Problems of Existing Algorithm

RA:

A node can get updated with the new information more than

once.

PKA:

Theoretically significant but not practical to implement.

Complete system needs to be informed after each information

transfer.

Difficult to implementation due to synchronization and

replication issues.

VTA:

Single node failure can stop spreading updates.

Thesis Objectives

Our main objectives for this thesis-

Bypassing information in case of single node failure.

Comparison between single node failure & no node failure.

Mapping between multiple databases, in order to searching

and retrieving information.

How Proposed System Works??

Databases are connected with one another.

They are creating a backup link for each of them.

In case of single node failure, rest of the databases can share or

get the data using this backup link.

System Architecture

Figure 10: System Architecture

Single Node Failure Problem

How system works for single node failure ??

Retrieve data, by searching query and query validation.

Information is disseminated by bypassing,

Using backup link, information is retrieved for search query.

Continue……

Database-1

Database-2 Database-4

Database-3 Database-5

Database1 -> Database 2

Database 2 | Database 3

Database 1 -> Database 4

Database 4 | Database 5Database 2 | Database 3 Database 4 | Database 5

Figure 11: Single Node Problem Solution

Continue……

Database-1

Database-2 Database-4

Database-3 Database-5

Database1 -> Database 2

Database 1 -> Database 4

Database 2 | Database 3

Database 4 | Database 5

Figure 11: Single Node Problem Solution

Database Mapping

Database Mapping :

Databases are independent.

Mapping between several databases tables & mapping

table is created after mapping, where all attribute value is

present without any replication.

Continue …

Figure 12: Database Mapping

Experiments and Result Analysis

Information retrieve with single node failure takes much time than

without node failure.

Relationship between data position & retrieve time is altered.

Computation time is increased with respect to data position.

Continue….

Computation Time:

Several Databases:

Continue….

Figure 13: Relation between data position & computation time

Conclusion

In this thesis, we have successfully retrieved information

instead of single node failure by storing backup path

information.

We have faced some difficulties like several servers, several

computer and several databases for researching this databases.

In future, multiple node failure problem of virtual tree algorithm

will be solved.

References

Reetu Dhar , “Performance Evaluation of Gossiping

Algorithms”, Southern Connecticut State University ,2009.

Róbert Ormándi, István Heged˝us and Márk Jelasity , “Gossip

learning with linear models on fully distributed data”, Wiley

Online Library (wileyonlinelibrary.com), 2012.

A.M. Kermarrec and M.V. Steen, “Gossiping in distributed

systems,” in ACM SIGOPS Operating Systems Review, vol.

41, iss. 5, pp. 2-7, 2007.

Thanks for your

Attention

Thank You

Any Questions?