Polling, or polled operation, in computer science, refers to actively sampling the status of an external device by a client program as a synchronous activity. Polling is most often used in terms of input/output (I/O), and is also referred to as polled I/O or software-driven I/O. From [Wikipedia on ...

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Does Windows Task Scheduler and smartphone alarms use polling?

I've been wondering, does Task Scheduler and phone alarms use polling? If not how does it work? And if they do poll to check the time, why isn't it cpu intensive and battery draining?
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130 views

How to check if app is offline

I am developing internal Android apps for the company I work for. In various places in the apps I need to connect to an internal server. This server is shutdown for maintenance for a period of time ...
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35 views

Listing search/query results from 30+ web services efficiently and orderly

We have a system that currently has approx 25 customers (will never expand from this) that each have a public facing web service which allows each other to query each others internal application ...
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79 views

How to to design a cronjob-like requirement

I have to design a system where I need to make some processing (which might take say 10 mins). After some amount of time (say 30 mins), I need to come back and check the status of this processing ...
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1answer
141 views

In a polled interface, is it okay for an object representing hardware to start a task responsible for the polling?

I am a hardware/test engineer currently writing a C# application for a device that does not have any event/interrupt mechanisms. Because of this I am forced to poll the device's internal control ...
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1answer
68 views

Polling without timestamp [closed]

I currently have a requirement to conduct polling in a network where new systems may log into anytime. The idea is that whoever comes online first goes into mode1 while the second guy goes into ...
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1answer
111 views

How to calculate how often to poll the server for new data? [closed]

Is there a formula, or generally accepted approach? Should I be measuring database updates and averaging their frequency then using that to determine how often clients should poll the server? I ...
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4answers
360 views

Is it true that for Observer Pattern to work, there probably is some polling mechanism underneath?

The short question is: is it true that for Observer Pattern to work, there probably is some polling mechanism underneath? (update: in a network situation) It was quite amazing that if on my Macbook ...
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2k views

How is spinlock different from polling?

Is spinlock and polling the same thing? Wikipedia: a spinlock is a lock which causes a thread trying to acquire it to simply wait in a loop ("spin") while repeatedly checking if the lock is ...
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685 views

How do I balance 100 clients checking the same database table in a loop?

What I have This is a prototype. I have a pool of 100 clients connected to the server via websockets reporting things and awaiting for commands. The server polls the commands database table of type ...
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598 views

Does the issue of battery life for constant polling warrant the extra logic/time to implement a solution with websockets?

I am in the process of designing a chat application with cordova for android devices. I have been researching and have come to the conclusion that there are two ways to go about this that could work. ...
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Polling more recent / active items more frequently

I'm setting up a service that is meant to query, via a rate-limited API, a number of posts in real-time. Now, some of these posts can be several months old, and they should really only be queried, say,...
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257 views

Pattern for checking online service availability

I'm not sure that this is entirely on-topic, but I'll try to make it so. I have an online service (API) and an Android application that uses it for all actions in the app. At the current moment, ...
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2answers
400 views

Periodically polling an API, are there alternatives?

I'm currently working on a service that is supposed to aggregate data from a number of APIs, unify the data, and offer it through another API to the users. I had a couple of ideas for solving this, ...
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56 views

Storing last polled database timestamp unix

I have a Unix script which is called by a scheduler (CTRL M) every 3 seconds. The script queries an external database(not belonging to my application and therefore I can only query it) to check for ...
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3answers
489 views

Avoiding polling with components

Once you create separate components that need to communicate with each other you enter the realm of systems programming where you have to assume that errors could originate at any step in the process. ...
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8answers
16k views

Why is polling accepted in web programming?

I am currently working on a Ruby on Rails project which shows a list of images. A must-have for this project is that it shows new posts in realtime without the need of refreshing the web page. After ...
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1answer
406 views

Should I use session or cache to keep the time it last polled when polling to server at intervals?

I'm building a web chat app using session to keep the time the app last polled so that the server can determine whether messages exist between the current polling time and last polling time. It works ...
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2answers
616 views

Polling vs events pros and cons in JavaScript

I'm bit of a novice to JavaScript so I've been wondering on positive and negative sides of using polling compared to using events in JavaScript? When does one use one or the other? By polling I ...
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445 views

Managing child worker thread list

After so much research, I thought I should ask the experts. I am working on a project for my corporate employer, we have android and iPhone mobile apps that make request to a web service, the request ...
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3k views

Push vs Poll when large delay (hours) is acceptable

It seems commonsense nowadays that polling is a bad practice and pushing is the way to go when developing mobile applications that require to constantly receive data from a remote server. All major ...
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3answers
438 views

Are there algorithims for polling optimization?

I have a web-application with an async HTTP backend, which gets called by the client by AJAX requests. The client has to start a job and then polls for the result. I started with a simple 150ms ...
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1answer
483 views

Best approach for near real time message passing from server to client across router?

I am developing an application which must run on up to thousands of client systems that I control (Linux) which are connected behind common NAT devices to public Internet. Each of these client ...
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2answers
668 views

What term is used to describe running frequent batch jobs to emulate near real time

Suppose users of application A want to see the data updated by application B as frequently as possible. Unfortunately app A or app B cannot use message queues, and they cannot share a database. So ...
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3answers
649 views

Scalable solution for website polling

I'm looking to add push notifications to one of my iOS apps. The app is a client for a website which doesn't offer push notifications. What I've come up with so far: App sends a message to home ...
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726 views

Design For Asynchronous User Interface

I have been working on a integration that has posed an interesting user interface conundrum that I would like suggestions for. The user interface is displayed within a third party product. The state ...