University of Gondar
Faculty of Informatics
Department of Information Technology
Post Graduate program (Extension)
Distributed Database System
Article review on: How Fast can a Distributed Transaction Commit?
Submitted to:
Dr.Muluneh
Submitted by:Haile
Yohannes
Mar, 2022
Gondar, Ethiopia
Objective
Reviewing the paper and preparing review report.
Introduction
Transactions were first used in the 1970s to ensure the consistency of distributed database
systems despite concurrency and failures, and they are still widely used today. Many current
distributed information systems, such as HP's Sinfonia and Yahoo's PNUTS, are transactional.
Percolator and Spanner from Google, Clock-SI from Clock-SI, and Yesquel from Yesquel. The
fundamental atomic commit problem is at the foundation of those distributed transaction
processing systems. Consider a distributed database system, such as Helios, that ensures the
serializability of transactions by tracking their concurrency ters (nodes). In other words, each
datacenter decides whether or not to terminate each transaction that produces a conflict. If no
datacenter discovers a conflict, the transaction is committed.
The Problem in Context
The following are problems that are addressed by the study:
1. The researchers exhaustively study complexity in the cases between two extremes,
assuming certain robustness of an atomic commit protocol.
2. This paper examines the time and message complexity of the atomic commit problem, as
well as the exact tradeoff between resilience and best-case complexity (as described by
Lamport), that is, the complexity of any failure-free execution where all processes vote to
commit.
3. This research investigates complexity in instances that fall between two extremes,
provided that an atomic commit mechanism is robust.
Material and Methods
The Data
o The researchers consider the problem of non-blocking atomic commit (NBAC) in the
classical sense of Skeen, which was later.
o A good execution of an atomic commit protocol is defined in this study as a failure-free
execution in which every process offers. This work's complexity is based on the becase
scenario, that is, the complexity of good executions (which are arguably the most
common in practice).
o The number of messages and the number of message delays are two complexity
measurements used by researchers.
The methods
 Unlike their understanding, theirs does not discriminate between the arrival and
departure of Complexity of Atomic Commit.
 The researchers create and exploit "implicit" votes for the willingness to commit in order
to design their best methods.
 "Helping" is another strategy used by the researchers. If some failure arises in order to
achieve the minimum number of messages or message delays in any nice execution, then
processes must seek for assistance.
Motivation of the study

A fault-free execution of an atomic commit protocol in which each process proposes

The number of messages and the number of message delays are two complexity
measurements.

A message delay is the time between two events: the transmission of m and the reception
of m, for any message m.
Evaluation of the proposed solution
 The researchers provided the INBAC procedure. INBAC addresses the issue of
indulgent atomic commit, as described below. According to the researchers, this
protocol is practical since it is well-suited to synchronous distributed database systems
"most of the time."
 A side from the complexity-robustness tradeoff (which attributes are required in which
execution)
 The researchers also highlight a tradeoff between time and message complexity.
 The researchers show that the optimal number of message delays and the ideal number
of messages cannot be reached at the same time in 18 of the 27 problem variations.
Criticism
Strong point of the study
 The researchers present here a protocol, which study denote INBAC, and which is delayoptimal as well as message-optimal given the optimal number of message delays.
 The researchers also present optimal protocols which may be of independent.
Weak point of the study
 Optimal commit latency is attained in failure-free executions. In terms of complexity, the
proposed technique is far from ideal in network-failure executions. With more
sophistication, our INBAC protocol might be modified to Helios' demands.
 Indulgent atomic commit is the most robust atomic commit problem
Conclusion
The first extensive examination of the complexity of atomic commit, both in terms of time and
message, is presented in this article. Lower bounds and matching approaches, as well as answers
to particular atomic commit difficulties, are proposed by the researchers. There are still some
unsolved questions. Given a tradeoff between time and message complexity, the best number of
messages for every atomic commit with more than two message delays, for example, remains
uncertain, even if they close the question for two message delays. According to this paper, a
network breakdown happens. An eventually synchronous system's execution can be fault-free,
have crash failures, or have network failures. This work investigates two measures of
complexity, the traditional notion of number of messages and the number of message delays, in
the wake of Lamport's consensus complexity study.
REFERENCES
J. Gray, “Notes on data base operating systems,” in Operating Systems, An Advanced Course,
1978, pp. 393–481.
L. Lamport, R. Shostak, and M. Pease, “The byzantine generals problem,” ACM Trans.
Program. Lang. Syst., vol. 4, no. 3, pp. 382–401, 1982.
D. Skeen, “Nonblocking commit protocols,” in SIGMOD ’81, pp. 133–142.