Questions tagged [distributed-systems]
Questions about the challenges of solving problems with multiple cooperating but separate agents.
133
questions with no upvoted or accepted answers
8
votes
0answers
82 views
Distributed Storage for Access and Preservation
My organization wants to maintain multiple copies of data in order to preserve access in the case of localized disasters as well as for the purpose of long term preservation. Are there accepted formal ...
6
votes
0answers
92 views
What is 2g-precedence?
I am currently reading a couple of papers about event processing. In the context of ordering events, "2g-precedence" is frequently mentioned. I don't know what it is, and I cannot find much ...
5
votes
0answers
42 views
Uni-directional synchronization and locking issues
Suppose there are two databases, $D_1$ and $D_2$. Let's further assume $D_1$ is always up and $D_2$ can be down sometimes. When it goes up again, it has to restart.
$D_1$ is filled by say a dozen ...
4
votes
0answers
43 views
What are some advanced background topics I'll need for distributed systems and networks research?
I am a new graduate student in Computer Science who would like to be able to read and understand modern and new distributed systems research papers. My current background / courses and understanding ...
4
votes
0answers
74 views
What distributed consensus algorithms don't rely on a time source?
I'm looking for information about distributed consensus algorithms that:
maintain a consistent transaction log across all healthy nodes
have similar high-availability properties to Paxos (i.e. not ...
4
votes
0answers
730 views
Even distribution algorithm
Right now I am working on a distributed system that sends messages from single source to many nodes. It is necessary that certain messages are sent to the same node to ensure order of processing. ...
4
votes
0answers
530 views
Is there any theory behind GraphQL?
GraphQL is a query language for your API, and a server-side runtime for executing queries by using a type system you define for your data.
Source: http://graphql.org/learn/
So GraphQL allows a ...
4
votes
0answers
58 views
How to realize a distributed queue with unreliable participants?
I want to build an application that relies on a distributed queue with participants in a decentralized (peer-to-peer) network. The participants cannot be relied on to correctly follow a protocol.
I ...
4
votes
0answers
107 views
Optimal schedule for broadcasting a file in a complete graph with overheads
I am trying to solve the following problem and despite having performed quite extensive literature review, I do not seem to find any similar problem or technique that would be useful here.
PROBLEM ...
4
votes
0answers
63 views
Extending the causal memory model to wide-area distributed storage systems
In the seminal paper "Causal memory: definitions, implementations, and programming", distributed causal memory is defined to ensures that all the processes in a system agree on the relative ordering ...
3
votes
0answers
19 views
How does a single-node system get Availability in CAP theorem?
I have a question. I read many blogs, websites about CAP theorem. They say that single-node systems are CA, but how can it be "A" if that single node goes down ? Because if it does, the ...
3
votes
0answers
47 views
Why does the proposer sends an accept request with the same value it got from the acceptor?
In the second phase of the paxos algorithm, the proposer issues an accept request with the number n and the value v it got from ...
3
votes
0answers
126 views
What are the theoretical and practical contributions of Multiagent Systems to science?
Speaking about multiagent systems (MAS) is about as fuzzy as talking about artificial intelligence systems (AI). They are in essence the distributed counterpart of AI.
While there are no so-called "...
3
votes
0answers
640 views
How to generate globally unique timestamps for transactions in distributed database systems?
According the paper [1] (Section 4), timestamp ordering (T/O) is a technique whereby a serialization order is selected a priori and transaction execution is forced to obey this order. In the following,...
3
votes
0answers
5k views
totally ordered multicast with Lamport timestamp
I'm studying Distributed Systems and synchronization and I didn't catch this solution of totally ordered multicast with Lamport timestamps. I read that it doesn't need ack to deliver a message to the ...
3
votes
0answers
128 views
Why does a prepare message wants a promise that an acceptor is never to accept a proposal numbered less than its propose sequence value? (Paxos)
I was studying Paxos from:
http://research.microsoft.com/en-us/um/people/lamport/pubs/paxos-simple.pdf
Recall that Paxos is a distributed system algorithm with the goal that the processes ...
3
votes
0answers
164 views
Proof of message complexity on the network
I try to provide a strict and mathematical rigorous proof to the following problem in Distributed Algorithms.
Prove or make a contradiction: if to vertices $a$ and $b$ on the network $G$ are located ...
3
votes
0answers
71 views
How is amorphous computing different from spatial computing?
Surely spatial computing and amorphous computing share similarities and overlap. Is spatial computing a subset of amorphous computing? How are the two different?
2
votes
0answers
42 views
Is this simple Asynchronous Byzantine Consensus Protocol correct?
I'm trying to solve a problem that may arise in a system I am concerned with. It will be uncommon in practice, so I am more concerned about simplicity and correctness than performance. I have N ...
2
votes
0answers
15 views
Minimum number of registers for mutual exclusion
I was reading distributed algorithms (by Nancy lynch) and there is a part that I would kindly like to get a simpler explanation for.
I know the book mentioned no algorithm can solve mutual exclusion ...
2
votes
0answers
25 views
Distributed transaction problem
Let's suppose there are two banks, Bank A and Bank B. A transaction needs to happen that transfers money from an account in Bank A to an account in Bank B. Bank A and Bank B have separate banking ...
2
votes
2answers
148 views
Ordering of operations in a DAG of git commits
Context: I'm looking for a better state resolution algorithm for https://github.com/MichaelMure/git-bug
Summary of the current algorithm and shortcomings
git-bug is a distributed bug-tracker that ...
2
votes
0answers
63 views
Using vector clocks vs. directed acyclic graph for causality detection in distributed systems
I'm trying to understand how vector clocks compare to DAGs for causality detection in a distributed system.
When trying to detect causality relations in a distributed system, a very commonly proposed ...
2
votes
0answers
99 views
Why is the 'Integrity' property required in consensus protocols?
Formally a consensus protocol must satisfy the following three properties:
Termination
Eventually, every correct process decides some value.
Integrity
If all the correct processes proposed the same ...
2
votes
0answers
27 views
Finding the timestamps of processes implementing Lamport's clocks
I have been asked this question, but don't know how to go about answering it.
Three process, which are implementing Lamport's clocks, are running and a lot of events are taking, place including some ...
2
votes
0answers
67 views
Leader election in synchronous ring with unreliable communication channels
As a part of my Distributed Systems course I am required to provide an algorithm that is able to elect a leader in a synchronous bidirectional ring, where every message that is sent may be lost (lets ...
2
votes
0answers
36 views
Distributed algorithms for finding n largest elements
It's easy to come up with a simple distributed algorithms for finding the maximum element in a set (totally ordered): Divide and conquer.
There are a few publications that present algorithms for ...
2
votes
1answer
476 views
What's the difference between strong consistency and sequential consistency?
How to Make a Multiprocessor Computer That Correctly Executes Multiprocess Programs
... the result of any execution is the same as if the operations of all
the processors were executed in some ...
2
votes
0answers
58 views
Distributed Computing: Persistent Data Structures in Functional Programming versus Wait-Free Data Structures
Persistent (aka immutable) data structures in functional programming sidestep issues of shared memory mutual exclusion, and thus also issues such as data races that arise and which may be difficult to ...
2
votes
0answers
41 views
Algorithms / heuristics for a distributed sorting problem
The setting:
There's a cluster of $k$ computers (= nodes). For simplicity, assume their hardware is identical.
The network topology can be complicated, but let's simplify and assume it's a clique ...
2
votes
0answers
77 views
Why is a primary node needed in pBFT algorithm for consensus?
Why is primary needed in pBFT algo? Since many issues of viewchange etc. come up because primary may be faulty - is it possible to have a version of pBFT which doesn't have nodes assigned as primary? ...
2
votes
0answers
181 views
Byzantine generals (n=3, m=1)
Leslie Lamport describes a algorithm to come to consensus for the case for n>3*m, there m is the number of traitors in ...
2
votes
0answers
632 views
How to compare distributed systems and big data
Are there scientific papers that compare distributed systems and big data processing systems?
Big data processing systems can be batch processing systems or streaming big data processing systems.
A ...
2
votes
0answers
117 views
Are Synchronous Message Order and Total Message Order separate concepts?
I am currently studying this book on distributed systems. In the chapter on message ordering the authors appear to use the term total message ordering and synchronous message ordering interchangeably. ...
2
votes
0answers
57 views
Auction website with Paxos consensus algorithm
As a project, I'm trying to construct a P2P auction web application with paxos in a high latency environment. The idea is that each user visiting the website will keep a small log file with the ...
2
votes
0answers
62 views
Distributed consensus feasibility from graph structure
Consider a consensus process in which participants
Initially take a position
Receive positions only from their neighbors
Accept a new position that is a super-majority of neighbors positions.
Under ...
2
votes
0answers
72 views
What is the largest number of Byzantine failures that can be tolerated in an $m$-dimensional hypercube for the consensus problem?
We are given a system with $n$ nodes which have been arranged into the topology of a hypercube of $m$ dimensions. I would like to derive a tight bound on the maximum number of Byzantine failures that ...
2
votes
0answers
61 views
Floating output/making a non-self stabilizing algorithm self stabilizing
So we're using this book by Shlomi Dolev on self-stabilization in class. Not being from a theretical CS background, I think the book is rather terse. Most of it is fine but there's this section on "...
2
votes
0answers
56 views
Find the size of the maximum cycle in a MPS
Consider the following problem to be solved in a distributed context:
Find for each processor the size of the biggest cycle of which it is member.
My algorithm is the following (for synchronous ...
2
votes
0answers
50 views
Distributed push relabel with changing graph topology
There is at least one (1) distributed version propsosed for the push-relabel maximum-flow algorithm. I wonder if and how this algorithm can cope with nodes leaving or enterig the graph during runtime. ...
2
votes
0answers
46 views
Polylogarithmic value-bounded concurrent data structures such as max register, counter, and monotone circuit
While reading the research paper Polylogarithmic Concurrent Data Structures from Monotone Circuits [@JACM'2012] by James Aspnes, Hagit Attiya, and Keren Censor-Hillel, I am not sure about some points ...
2
votes
0answers
287 views
Efficiently estimating latency quantiles of a distributed system
I'm building a load test harness for a distributed system. Currently I'm using the "Cormode, Korn, Muthukrishnan, and Srivastava" method to estimate latency quantiles of system responses.
I'm now ...
2
votes
0answers
72 views
Throughput measure
I have to implement a limitation algorithm in order to avoid to reach a throughput limit imposed by the service I'm interacting with.
The limit is specified as «N request over 1 day» where N is of ...
2
votes
0answers
1k views
k-Trees Graph Coloring
There is an exercise in Distributed Algorithm I have some difficulties to solve. There are few ideas, however nothing useful at the time. I will appreciate any help with it.
Graph $G$ is a $k$-tree ...
1
vote
0answers
6 views
How do distributed joins work in a distributed relational database system?
I have been looking around for a few days trying to find a clear and concise description of how, at a technical/implementation level, how distributed joins work, but haven't found much. The best so ...
1
vote
0answers
47 views
Can decentralised systems mitigate 51% attacks by design?
Can you make decentralised systems, e.g. cryptocurrencies or serverless games, that aren't susceptible to 51% attacks by design? (Rather than, as I've seen proposed, external solutions like fining ...
1
vote
0answers
26 views
Modern standard texts on distributed systems
I'm starting a job soon that involves a large number of disciplines interacting at once. I'm knowledgeable in most of these areas; at least enough that when I don't know something I know how to look ...
1
vote
0answers
22 views
Bully Algorithm Timeout After Receiving a Response from a Higher Process
Im specifically referring to the bully algorithm for synchronous systems, described in [Garcia-Molina 1982]. In it, the timeout for failure detection is concretely defined as the sum of the round trip ...
1
vote
0answers
306 views
How is this example sequentially consistent but not linearizable?
Background information that I know(But not understand with examples, I will be glad if you could explain it to me with examples)
A replicated service is said to be linearizable if for any executin ...
1
vote
0answers
11 views
Distributed Graph Consensus to fit a distribution?
$G$ is a strongly connected graph with nodes $V$ and edges $E$. Each node $v_i$ receives a sample $x_i$ from a Gaussian $\mathcal{N}(\mu,\sigma^2)$ with unknown mean and variance.
The objective is for ...
