Toots for jepsen@jepsen.io account

Written by Jepsen on 2025-01-22 at 14:40

Woke up to a bunch of excellent emails--y'all rock. Will try to write back to everyone in the next hour or so. ❤️

=> More informations about this toot | View the thread

Written by Jepsen on 2025-01-21 at 23:35

So, uh, the last time I had to call malloc() was a quarter century ago, and I am struggling to do basic tasks without corrupting the heap. I would love to hire one of you stripey-socked C witches for a very small contract to help finish https://github.com/jepsen-io/jepsen/blob/main/jepsen/resources/corrupt-file.c. Goals:

1.) Fix my really obvious mistakes.

2.) Add appropriate calls to free(ptr).

3.) Spend an hour or two talking me through your changes so I can Not Mess This Up So Badly next time. 😁

Interested? Email aphyr@jepsen.io.

=> More informations about this toot | View the thread

Written by Jepsen on 2024-12-22 at 21:02

Added descriptions of the SQL isolation level anomalies P0, P1, P2, and P3 to the phenomena page: https://jepsen.io/consistency/phenomena#sql

=> More informations about this toot | View the thread

Written by Jepsen on 2024-12-04 at 18:49

Released version 0.2.4 of Maelstrom, Jepsen's workbench for writing toy distributed systems: https://github.com/jepsen-io/maelstrom

=> More informations about this toot | View the thread

Written by Jepsen on 2024-12-04 at 18:29

There's a few tickets left for the distributed systems class coming up the week after next. If you'd like to join, now's the time. :-)

https://www.eventbrite.com/e/distributed-systems-fundamentals-registration-1060426286569?aff=mastodon

=> More informations about this toot | View the thread

Written by Jepsen on 2024-12-03 at 22:29

Bin Wang put together a Jepsen test for Patroni, a PostgreSQL replication system. All sorts of good stuff in here, including that the cluster can't handle a series of single-node failures: https://www.binwang.me/2024-12-02-PostgreSQL-High-Availability-Solutions-Part-1.html

=> More informations about this toot | View the thread

Written by Jepsen on 2024-11-27 at 16:02

Antithesis, Buf, and Jepsen are running a joint webinar on December 5th. We'll discuss a Kafka protocol safety issue, talk about the challenges of distributed systems testing, and show how Jepsen and Antithesis helped identify critical safety errors in Bufstream. Come watch Antithesis pause, rewind, and explore a running Bufstream cluster in an interactive debugging shell!

https://buf-8423972.hs-sites.com/taming-kafkas-behavior-using-jepsen-antithesis?utm_source=jepsen&utm_medium=partner&utm_campaign=2024-12-05-WB%2520Taming%2520Kafka%25E2%2580%2599s%2520Behavior%2520using%2520Jepsen%2520%2526%2520Antithesis

=> More informations about this toot | View the thread

Written by Jepsen on 2024-11-13 at 16:59

Thanks to everyone who wrote in objecting to the report's description of data loss due to auto-commit. Some experiments this morning suggest that we got it wrong (at least for the official Java client). We've published an update to the report: https://jepsen.io/analyses/bufstream-0.1.0#updates

=> More informations about this toot | View the thread

Written by Jepsen on 2024-11-12 at 15:49

"That's never been my understanding of auto-commit, that would be a crazy default wouldn't it?"

I feel like there's a real need for database user research--building a quantitative and qualitative picture of how actual users understand the systems they rely on. https://news.ycombinator.com/item?id=42116297

=> More informations about this toot | View the thread

Written by Jepsen on 2024-11-12 at 14:26

We reproduced lost writes, aborted reads, and torn transactions in Bufstream and Kafka. We believe every Kafka-compatible system is likely vulnerable to these issues. Some clients may be able to mitigate them, but the official Java client presently does not.

=> More informations about this toot | View the thread

Written by Jepsen on 2024-11-12 at 14:23

One of the surprising things we found during this collaboration was that the #Kafka transaction protocol assumes messages are delivered in order, but allows those messages to be delivered to different nodes over different TCP connections. This means that a client's commit or abort message could be applied to a completely different transaction, or even in the middle of a transaction.

=> More informations about this toot | View the thread

Written by Jepsen on 2024-11-12 at 14:15

A new #Jepsen report! We worked with Buf to analyze the safety of Bufstream, a Kafka-compatible streaming system. We found three safety and two liveness issues in Bufstream 0.1.0, including the loss of acknowledged writes in healthy clusters. These problems were resolved by version 0.1.3.

https://jepsen.io/analyses/bufstream-0.1.0

=> More informations about this toot | View the thread

Written by Jepsen on 2024-11-07 at 15:44

As an aside, I'm cackling that MariaDB saw the Extremely Queer genders in the test suite and decided to put "male" and "female" in their blog post instead. Except they put "male" in the name field, so... I dunno, somehow this version is even more trans? 😅

https://github.com/MariaDB/jepsen-mariadb/blob/d90be5b4a0b73d2c6272fbe6c72c855c20c323fb/src/jepsen/mysql/nonrepeatable_read.clj#L111

=> View attached media | View attached media

=> More informations about this toot | View the thread

Written by Jepsen on 2024-11-07 at 15:35

Last year we reported that MySQL and MariaDB's "Repeatable Read" was badly broken. The MariaDB team has been hard at work, and they've added a new flag, --innodb-snapshot-isolation=true, which causes "Repeatable Read" to prevent Lost Update, Non-repeatable Read, and violations of Monotonic Atomic View. It looks like MariaDB might, with this setting, offer Snapshot Isolation at "RR". :-)

https://jepsen.io/analyses/mysql-8.0.34

https://mariadb.com/resources/blog/isolation-level-violation-testing-and-debugging-in-mariadb/

=> More informations about this toot | View the thread

Written by Jepsen on 2024-10-25 at 23:20

If you've been waiting for a chance to take Jepsen's distributed systems class, we've got great news. We're running a special session December 16-19 that anyone can register for.

https://www.eventbrite.com/e/distributed-systems-fundamentals-registration-1060426286569?aff=mastodon

=> More informations about this toot | View the thread

Written by Jepsen on 2024-10-24 at 15:50

Just want to give a shout out to Irene Kannyo, who's edited every Jepsen analysis over the last four years. She brings her background as scientist and writer to our industry-focused reports, maintains an evolving style guide, streamlines prose, ensures diagrams match descriptions, and so much more. If you need help with technical or culture writing, she's stellar.

https://irenekannyo.com

=> More informations about this toot | View the thread

Written by Jepsen on 2024-10-21 at 20:21

Shoot! Caught a cold on Thursday and I'm still not quite over it. Won't be able to make it to GOTO after all. Sorry y'all. 😔

=> More informations about this toot | View the thread

Written by Jepsen on 2024-10-18 at 19:16

[#]Jepsen 0.3.6 is now available on GitHub and Clojars. This is a sizeable release. It includes a significant correctness bugfix for a rare bug that could make operations in the history print with the wrong data. It also adds a new namespace for composing databases, nemeses, and generators when working with systems where each node has a different role. Kafka-style tests gain new powers and are significantly faster.

https://github.com/jepsen-io/jepsen/releases/tag/v0.3.6

=> More informations about this toot | View the thread

Written by Jepsen on 2024-10-15 at 17:11

Just a heads-up: I'll be speaking at GOTO Chicago next Tuesday, 2024-10-24, on JVM performance techniques in Jepsen:

https://gotochgo.com/2024/schedule?date=2024-10-22&video=false

=> More informations about this toot | View the thread

Written by Jepsen on 2024-08-29 at 20:26

Jepsen 16: I Can't Believe It's Not ACID, delivered at Systems Distributed 2024. RavenDB, MariaDB/MySQL, Datomic.

https://www.youtube.com/watch?v=ecZp6cWhDjg#t=45s

=> More informations about this toot | View the thread

=> This profile without reblog | Go to jepsen@jepsen.io account