Questions tagged [stream-processing]

Stream processing is consuming an input stream or sequence of bytes with some format, processing the data as it arrives, and translating it into another format in a related output stream.

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63 views

API for input stream operation read until

I want to create a stream class The input stream should read/parse a continuous range from left to right providing convenience methods. The implementation isn't a problem but choosing a consistence ...
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1answer
76 views

Showing posts by their time-decayed score

I want to show a number of posts, ordered by their score, limited to some number. The score is the product of the number of likes they have (from another table) and the recipricol of their normalized (...
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Bigdata architecture: persisting raw data and streaming them at the same time

In a case where we have multiple source of data, we need to : persist each source of data in its raw form. process the data source eventually with each other to transform them in a presentable state (...
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75 views

Design for Maintaining changes over time which supports arbitrary updates in different time points

I have a collection of documents, which hold a subject id, a timestamp and a value. For example: { sid: 1, t: 3, v: "A" } { sid: 1, t: 5, v: "B" } Which means subject#1 is ...
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How are different resolution settings for videos handled by server and client based on setting and connection speed? [closed]

I was watching youtube and squinted at the text in the video and wondered what happens when I switch from 720p to 1080p. Does the streaming service, Youtube and or any other, just have the files in ...
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Do 1:1 mobile video call face filters belong on Client or Server?

I am drafting architecture for 1:1 video calling mobile app with face filters (face recognition). I could use p2p e.g. WebRTC because more savings less complexity. However, continuous face rec during ...
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2answers
103 views

IO stream interface in C

When writing a library (eg. for dealing with JPEG or PNG files), the first thing library author needs to provide is an abstraction over FILE* (to allow also reading from plain memory, pipe, socket, ...
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1answer
46 views

System design to store pieces of data with specific ttyl to then refetch

I have a system which generates pieces of data that needs to be tracked and assigned a specific TTYL value (a value in seconds) for how long they are supposed to live before being re-processed. I ...
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1answer
108 views

How to keep a data warehouse updated?

Suppose there is a system ( like an ERP ) that writes to a database ( not too big, less than 100GB ). You need to export the data from this database to a data warehouse ( like RedShift or BigQuery ) ...
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1answer
93 views

what is the correct OOP way to read/write binary data if meta information of how data is encoded is stored inside data itself?

I have a Buffer which wraps a stream of binary data. The first byte indicates order, either big endian or little endian, which is needed to unpack the data. class FooBuffer implements Buffer is ...
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1answer
41 views

Event Processing a Lack of Events

I am facing an issue that I don't believe is novel but none the less am having trouble finding a solution that fits well with our system. We have a constant stream of events going into AWS Kinesis. ...
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3answers
329 views

What is the right algorithm to match regex on a stream?

I'd like to match a regex pattern on a stream, but I am not sure what algorithm to use. I certainly don't want to load the entire file into memory. I tried to figure out how to do this, but I have ...
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1answer
72 views

Transitive matching in streaming application

Problem A streaming application should perform matching transitively i.e. if A == B & B == C then A == C Current Implementation Application accepts domain objects in a streaming fashion and ...
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1answer
465 views

Generate large Excel files and response from API

I need to generate a large Excel file (something around 50 megs) and send response to another API which will provide it to the front end for a download option. My question is if it will be better to ...
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1answer
212 views

Are streams of binary data considered a form of bit banging?

Are streams of binary data considered a form of bit banging? Does this definition change if the array is buffered? I am referring software which handles binary data on a general purpose CPU; for ...
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1answer
209 views

What is the relationship between reactive programming and stream processing engines?

When would I use reactive programming libraries like RX Java and Project Reactor compared to stream processing engines such as Storm and Flink? I am aware that these concepts might not be directly ...
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1answer
88 views

How should I approach the comparison of two BMP images?

I am currently writing a Python program that retrieves the pixels from two BMP files and finds the percent difference between them (without using the Pillow library for the purpose of learning). I can ...
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247 views

What are the distinction and relation between batch processing and stream processing systems?

Design Data Intensive Applications says Batch processing systems (offline systems) Chapter 10 A batch processing system takes a large amount of input data, runs a job to pro‐ cess it, and ...
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What could be a good scalable alternative to polling data and then looping over a list of objects for triggering some action on those?

So I have some naive implementation for the following problem: We have a list of objects with action methods that have to be trigger at some value of interest. This value is polled (or is streamed) ...
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47 views

Efficient Options to do Stream Joins(with Large Time gaps)

Use Case: I need to join two stream sources(say orders(order_id, order_val) and shipments(shipment_id, shipment_val)) based on an id(order_id = shipment_id) and generate a new event shipment_order(id, ...
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243 views

Data pipeline architecture: airflow triggered by message broker

Let us say we have: a web app with a Postgres DB that produces data over time, another DB optimized for analytics that we would like to populate over time. My goal is to build and monitor an ETL ...
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1answer
97 views

Solving Event Dependence in Event Driven Systems

There are 60 Million Shipments per day. Each shipment has about 50 metrics to be calculated. Each metric is calculated based on a type of the event(Let's say event_1 has the required information to ...
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0answers
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Moving application control flow from NiFi to code

We currently have an application that is nominally written in Java/Spring boot, but all of the control flow is in NiFi. For example, there are the following layers in the java application: ...
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265 views

Is the concept of Rx debounce possible in a distributed environment?

The issue I am building a server-side system that handles streams of time-series events from multiple users and I'd like to perform an action after a certain quiet period has elapsed in the event ...
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1answer
64 views

Aggregating events in event-driven system

Lets say there are two services. One generates event A and the other event B. We need to build a new service that implements the function C = func(A, B) , which produces the result C. But as A and B ...
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1answer
61 views

Best practices for fixing bugs in event stream processing [closed]

We are working on an event driven system that works a streaming technology (eventhub/kinesis/kafka). Imagine some system is generating events that are sent to the event stream. Then there are ...
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1answer
8k views

Download file stream as it's being generated

Scenario We are building a UI that allows users to query our data in bulk. The return format is CSV and there is a decent amount of processing that needs to happen, so this processing processing is ...
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1answer
149 views

What is a good technique to process an event stream to ensure sequential or transactional consistency

I am trying to improve an event-driven processing system, which is having a few problems because the events are not guaranteed to arrive in the correct chronological sequence. This is due to batching ...
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2answers
1k views

Java 8 - When should I use java.util.Stream instead of java.util.Collection?

I started studying functional programming with JavaScript. After this, I started to study it with Java 8 (streams, lambdas and method reference) and I realised that I tend to use streams as much as ...
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1answer
242 views

How to signal end of stream?

I am designing an interface for reading and writing video frames to various inputs and outputs. Stream operators seem to me a superb alternative to named functions for the task. This is the gist of it:...
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1answer
86 views

Why use apache spark instead of just a normal worker?

Why should someone use a stream processing engine like Apache Spark, Flink, Hadoop instead of just a normal backend worker which works on something and returns the results as soon as it's done? ...
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3answers
3k views

Why do you want to avoid flushing stdout?

I stumbled upon a question in Codereview, and in one answer the feedback was to avoid std::endl because it flushes the stream. The full quote is: I'd advise avoiding std::endl in general. Along with ...
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1answer
84 views

how simulate sequential consumers in Kafka

I have kafka consumer that get data from kafka and do some process if some circumstances meet and send it for another consumer to do it's job. How can i build something like this? One way I think ...
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1answer
97 views

Backend architecture for a datastore with real-time events?

I need to build a data store for transactions that meets the following requirements: A 'transaction' is effectively a state machine which moves through a number of statuses during its lifecycle and ...
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2answers
212 views

Ideal Interprocess Communication

So, there is a workflow I feel needs to exist. It may already exist, and I don't know about it. Consider the Linux command line workflow, the "motto" of Linux, more or less. You have a bunch of ...
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1answer
564 views

Short-circuiting an infinite Java 8 stream

Assume You have some POJO Animal like public class Animal { // some fields } You have some enum AnimalType like public enum AnimalType { // some animal types } You have some method that given an ...
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1answer
60 views

Best practices for reading dynamic byte streams: is line-by-line comparison with a mask the best way?

I receive sensor data as a binary stream of bytes. This stream is not always the same length, and does not include the same data set each time. If the sensor did not send a field, it is simply absent, ...
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2answers
169 views

Receive data in random order, send in order

I am facing an issue where I have a data stream that sends unordered data. I'm trying to find a way to receive the data in random order, but send it in order. As an example, I'll receive object4 and ...
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2answers
108 views

Are there any techniques for detecting redundancies a stream of changes to a filesystem?

I'm working on a file-synchronization client that currently produces a stream of changes to the underlying filesystem. That is a stream of create/update/move/delete events is produced for each ...
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1answer
607 views

Should I produce output with yield or stream.write in Python 3?

I am working on a Python 3 program that will among other things write data to text files in a number of formats. I have one function per format, generating the data to be written. I see two possible ...
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1answer
55 views

node server structure and technologies - support continuous and high volume (amount, not size) data transfare

I'm having trouble planning the structure of my server side workflow and the technologies I should use. The basic structure and tasks are: Now, things to consider: 1.the server listens to multiple "...
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1answer
258 views

Why is the sorted() method on Stream not named sort()?

Why is the sorted() method on Stream not named sort()? list.stream().sort()
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2answers
2k views

What are reactive streams and what's so special in them?

I browsed Wikipedia and encountered a new feature of Java 1.9: Reactive streams. Unfortunately, the linked Wikipedia page doesn't help much to understand what those reactive streams are and what's so ...
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2answers
392 views

Are .NET Streams like 'real' streams?

To me a stream implies that I should be able to: Put things in one end and receive it from the other end in the same order. Do these things at the same time. i.e. continuously be adding to the top ...
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1answer
3k views

Usage of For-each loop vs functional operation vs Java8 streams

What are the gains in actual computing speed (verbosity of code being put aside) and for which case would each be recommended for, as a good design pattern? I would like to know the above in general ...
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2answers
7k views

Traditional Message Brokers and Streaming Data

According to the Kafka site: "Kakfa is used for building real-time data pipelines and streaming apps." Searching the internet far and wide, I've found the following generally-accepted definition ...
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4answers
1k views

What is a “streaming app”, exactly?

I'm trying to get past all the hipster, pie-in-the-sky buzzwording and address a very simple, fundamental question: What is a streaming application? According to the Kafka site "Kafka is used for ...
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1answer
189 views

Moving from Batch to Streaming architecture using a Graph datastructure

The use case I am trying to solve is, assigning millions of users to their groups/segments. I have thousands of different criteria from which buckets of users are created. E.g. bucket criteria: All ...
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2answers
907 views

Differences between streams and iterators in C++?

I'm working on code which will provide a generic C++ interface to relational datasets. Some of the data will be in tables in memory (e.g. std::set or std::vector), but some of it will be computed - ...
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5answers
276 views

Algorithm to limit the speed of processing items

I need to process a large number of data items, and I need to restrict the speed at which they are processed. For example, not more than 20 items per minute. I've thought about an algorithm for that, ...