Publishing Enriched Data Update Events
"When caching and "poor man's replication" play well together."

I've put together quite a few thoughts, and would appreciate external wisdom at how to approach them from the larger eng org standpoint.

https://dimakorolev.substack.com/p/publishing-enriched-data-update-events

The next — Educational — episode of the meetup is up.

Never confuse functional, integration, regression, and end-to-end tests again!

Moreover, don't take this very question seriously. For if you want to set things straight, offense is the best defense!

Video: https://tinyurl.com/sdm-testing-video
Slides: https://tinyurl.com/sdm-testing-slides

https://www.youtube.com/watch?v=y8OnoxKotPQ -- a really well done pun, many thanks to the kind soul in our Slack who shared it!

Sharing my longread on Event Sourcing here as well.

(Likely a topic for one of the next on-air meetups; we'll chat about it off the record as well, that's for sure.)

If my writing is too dense -- I'm working on style every day! -- this post on building real-time exchanges is very good too; I could have linked to it from my post, but, admittedly, forgot to.

I've published a longread about Event Sourcing, in the "Gentle Introduction" way.

The introduction is gentle both from the engineering standpoint and from the grounds of convincing the business to begin making the first steps.

If you struggle with justifying it to the stakeholders that the company needs to upgrade its data stack, or if you already have a soft buy-in but are unsure how to best proceed -- I hope you'd find this post helpful and insightful.

Yours truly designing Uber. Good to be on the other end from time to time, many thanks to Tom for interviewing me.

Also, I gotta work on being less confusing. Although think the conversation went quite well.

https://open.substack.com/pub/dimakorolev/p/the-oltp-language -- collected my thoughts on how can we accelerate the retirement of SQL as the meant to implement OLTP transactions.

Just clicked "Publish" on two posts that were in the works for well over a month. Behold:

• Distributed Stateful Workflows, and
• Stateful Orchestration Engines.

Hope you enjoy reading them as much as I enjoyed writing them. And spread the word!

The episode on Stateful Orchestration is out!

In reality this episode sets the table for proper introduction into the domain of stateful orchestration. I talk in detail about many SysDesign problems leading to formulating the problem, from the idea of serialization and vector clocks, through decoupling of producers and consumers, and all the way to Cadence and Temporal as generic mechanisms to enable SAGAs and more sophisticated patterns at scale.

Durable Execution, a.k.a. Stateful Orchestration 2.0.

The closing meetup episode of 2024 is now released.

https://tinyurl.com/sdm-durable-execution
https://tinyurl.com/sdm-durable-execution-slides

Would be great to build this together in 2025 and beyond!

#Milestone

I guess ... thank you — and looking forward to much more!

Folks, Maxim Fateev, the founder of Temporal has a super discount code — CSDM80 — for those of us who want to attend Replay 2025, https://replay.temporal.io/.

It's literally 80% off. Definitely good enough in my book to share with the community. Hope to see you there!

A very good catalogue, via @vanadium23.

https://muratbuffalo.blogspot.com/2021/02/foundational-distributed-systems-papers.html

Realistically, it looks like we'd do well to just build an open-source comparison tool for a few most popular cluster (i.e. decentralized) databases.

The list so far is quite large and growing:

⒈ FoundationDB
⒉ Yugabyte
⒊ CockroachDB
⒋ YDB

The test may well be the trivial "Alice pays Bob, no over-spending" app.

The cluster DB should run on three/five/seven nodes, an odd number.

Client nodes would be sending traffic either to all nodes at random, or to just one of them.

Failing nodes should also be tested, as well as slow/deteriorating network.

All can be done with docker-compose.

Invaluable experience, useful insights, open source code, a meetup episode or two of making this happen. All the good stuff.

Best way to build this, I think, would be to have think wrappers for each DB to a) start it, and b) provide some unified API layer for the above operations, so that each DB node is one-to-one paired with a thin API node.

So that the tester code can be independent of what DB is being used. Including sending the requests, verifying correctness of responses, measuring throughput/latency, and turning off the nodes and/or slowing down traffic between them at random.

Who's excited?

The lightning talks event from this week's SysDesignMeetup is out: https://tinyurl.com/sdm-lightningtalks-feb2025

It has three lightning talks.

• By David Archuleta, on Wasm and perfomant code in both the browser and node.js,

• By me, on Source-of-Truth, and how it relates to "learning to count", and

• By Alex Kantsevoi, on using etcd to perform leader elections and achieve consensus.

I'd say it's good content, although I'm still getting used to using the Mac and recording the screen from it. Enjoy!

I normally don't share upcoming off-the-record events of the SysDesignMeetup, but we had a break of a few months, and thus some extra visibility is warranted.

This Saturday. If you'd like to join, vote for the best time slot with a Slack reacc here.

To get to Slack, https://tinyurl.com/sdm-slack-invite should still work.

More details and links at http://github.com/sysdesignmeetup/sdm.

Hope to see you soon!

We're trying to make the Tail at Scale guest talk happen on August the 14th, which is a Thursday.

Morning US time, evening Europe time.

This is the paper, by Jeff Dean and Luiz André Barroso. It covers many topics dear to my heart, such as how to measure latencies properly, and what is request hedging.

If you want to make it, please vote on the best time slot in SysDesignMeetup's #general Slack, channel, and use this link to join if you're not there yet.

And here comes the official #announcement.

We have a talk planned on The Tail at Scale paper by Jeff Dean and Luiz André Barroso!

Jordan West is an Engineering Manager at Netflix and a Cassandra committer. He’s worked on large scale deployments of Cassandra for the past 7 years and distributed databases for the past 10. He is passionate about growing the Cassandra community and working on large scale distributed systems.

Save the date, Thursday, August the 14th:

San Francisco, USA 10:00 am PDT
New York, USA 1:00 pm EDT
London, United Kingdom 6:00 pm BST
Amsterdam, Netherlands 7:00 pm CEST
Istanbul, Turkey 8:00 pm EEST

Google Calendar event: link.
See you at http://zoom.dima.ai!

Published my thoughts on the very idea of durability scaling far beyond the "eleven nines" guarantee people expect these days: https://dimakorolev.substack.com/p/durability-of-distributed-systems