Tackling node failure in
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Transcript of Tackling node failure in
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??
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.
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
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
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.
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.
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.
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.