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henning

I thought this kind of bullshit was only supposed to happen in MongoDB!

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Then you haven't read enough jepsen reports. Distributed system guarantees generally can't be trusted

Postgres is not a distributed system in this configuration usually though is it?

The result is for “Amazon RDS for PostgreSQL multi-AZ clusters” which are certainly a distributed system.

I’m not well versed in RDS but I believe that clustered is the only way to use it.

No, you can have single instances

This writeup tested multi-AZ RDS for Postgres — which is always distributed behind the scenes (otherwise, it couldn't exist in multiple AZs).

An RDS cluster can have a single instance (but it can't be multi-AZ with a single instance.)

A multi-AZ cluster is necessarily a distributed system.

I think zookeeper is still the only distributed system that got through jepsen without dataloss bugs, though at high cost: https://aphyr.com/posts/291-jepsen-zookeeper

Didn't FoundationDB get a clean bill of health?

wasn't tested because: "haven't tested foundation in part because their testing appears to be waaaay more rigorous than mine."

https://web.archive.org/web/20150312112552/http://blog.found...

apparently wasn't tested because Kyle thought the internal testing was better than jepsen itself: https://abdullin.com/foundationdb-is-back/

Aphyr didn’t test foundation himself, but the foundation team did their own Jepsen testing which they reported passing. All of this was a long time ago, before Foundation was bought by Apple and open sourced.

Now members of the original Foundation team have started Antithesis (https://antithesis.com/) to make it easier for other systems to adopt this sort of testing.

Do people still use MongoDB in production?

I was quite surprised to read that Stripe uses MongoDB in the early days and still today and I can't imagine the sheer nightmares they must have faced using it for all these years.

mongodb is a public company with a market cap of 14.2 billion dollars. so yes, people still use it in production

I've been looking for a job the last few weeks.

Literally the only job ad I've seen talking about MongoDB was a job ad for MongoDB itself.

MongoDB has come a long way. They acquired a world-class storage engine (WiredTiger) and then they hired some world-class distsys people (e.g. Murat Demirbas). They might still be hamstrung by early design and API choices but from what I can tell (never used it in anger) the implementation is pretty solid.

MongoDB is a very good database, and these days at scale I am significantly more confident in its correctness guarantees than any of the half-baked Postgres horizontal scaling solutions. I have run both databases at seven figure a month spend scale, and I would not choose off-the-shelf Postgres for this task again.

Those memes are 10 years old, you know that some very tech company use MongoDB right? We're talking billions a year.

What is your point?

MongoDB is reliable.

Billion dollar companies lose their customer’s data all the time.

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