Skip to main content

A paper a day keeps the doctor away: The 8 Requirements of Real-Time Stream Processing

In recent years there has been an explosion of data all around us. The data comes in from a variety of sources, such as financial real-time systems, cell phone networks, sensor networks--RFID and IoT, and GPS. Commensurate with this dramatic increase in data, is a corresponding unquenchable thirst for analysis and insights. The natural question arises: how do we build systems that process and makes sense of this vast amount of data, in as close to real-time as possible? What patterns of software and systems should we look at?

Michael Stonebraker of database fame et al. offer some advice on what to consider in their paper: "The 8 requirements of real-time stream processing" published a decade ago. In the paper, the authors list eight guiding principles that high-volume low-latency systems should follow to be able to process vast amounts of data in near real-time.

First, the systems have to keep the data moving, and do straight-through processing with minimal to no writes to disk to achieve the low-latency desired. The authors compare passive (polling) systems versus active (event driven systems) and recommend the latter.

Second, the authors recommend supporting a high-level language--dubbed StreamSQL, with built-in extensible stream oriented primitives and operators to process the data instead of writing custom code in languages such as C++ and Java.

Third, the system has to handle stream imperfections such as delayed data, missing data, or out of order data, and have timeouts for potentially blocking data to ensure system liveness.

Fourth, the system has to integrate stored and streaming data, to be able to reprocess data when necessary.

Fifth, the system has to generate predictable outcomes and repeatable results, such as when it needs to reprocess data for recovery, or handling duplicate data.

Sixth, the systems have to guarantee data safety and availability, with uninterrupted fail-over between primary and backup systems ala "Tandem-style" computing.

Seventh, the system has to partition and scale applications automatically, between cores and across machines to be able to seamlessly handle any increase in load.

Finally, the system has to be quick, process and respond instantaneously to streaming data, which requires careful planning and coding to minimize boundary crossing, and maximize the ratio of useful work to computation overhead.

The authors examine common architectures that fulfill parts of the requirements they listed above including databases (DBMS), rule engines that are built on condition/action pairs, and stream processing engines. They present in tabular form where the systems excel at, and where they don't. The table leans toward using stream processing engines instead of DBMS which are not optimized for the task.

Despite being a decade old, the paper is still relevant, and referenced in the modern literature. Moreover, it is well written and a pleasure to read.


Comments

Popular posts from this blog

Kindle Paperwhite

I have always been allergic to buying specialized electronic devices that do only one thing, such as the Kindle, the iPod, and fitness trackers. Why buy these when technology evolves so fast that a multi-purpose device such as the phone or a smart watch can eventually do the same thing, but with the convenience of updates that fix bugs and add functionality? So, I was shocked when this weekend I made an impulse buy and got the newest Kindle Paperwhite—a special purpose device for reading eBooks. I was walking past the Amazon store in the mall and saw that the newest Kindle Paperwhites were marked down by $40 for the holidays. The device looked good in the display, so I went in to look at it closely. The Paperwhite is small and light, with a 6” screen that is backlit and waterproof.   The text was crisp and readable, and in the ambient light, it felt like I am reading a printed book. I was sold and bought it on the spot. At home I have struggled to put it down. The bo...

Emacs on WSL2: From Monochrome Misery to Modern Elegance

Windows Subsystem for Linux (WSL) has come a long way—especially under Windows 11 . WSL2 now offers smooth integration for Linux graphical applications, making it feel less like a compatibility layer and more like a native experience. But if you're an Emacs user, you might have noticed something off. Launching Emacs under WSL can feel like stepping into a time machine. Tiny fonts, washed-out visuals, and a UI that evokes the green-and-amber glow of vintage terminals. Functional? Yes. Pleasant? Absolutely not. But here's the good news: it is easy to make Emacs under WSL2 look just as sharp and modern as it does on Mac OSX . The emacs-pgtk build is designed for better graphical integration under WSL. It uses the Pure GTK interface , which plays nicely with WSL’s GUI support. sudo apt install emacs-pgtk To make Emacs look great, we’ll use Windows’ rich font library. First, edit your font configuration: sudo emacs /etc/fonts/fonts.conf and add the Windows Font directory...

MacOS Catalina, OneDrive, and case sensitive file systems

Over the weekend, I dusted off my old Macbook Air to search for some old family photos. I have not used the laptop for a long time, and it was completely out of charge. I plugged it in, and it quickly booted. Shortly after, I got bombarded with notifications that many of the applications needed updating, and that a new version of the OS was available.   I waited till I found the photos I was looking for, before attempting to upgrade anything. I also wanted to install OneDrive to get my old files to the cloud, so that I can access them from any of my devices, instead of dusting off old computers to get to them. The MacOS upgrade experience has always been fantastic, and this one was no different. The OS upgrade files downloaded quickly and after a restart and a quick install, the Macbook Air was ready to go.   Upgrading the installed applications was also a breeze, however in the process I discovered that a large majority of the applications installed were not compatible ...