The road to ACID transactions in Cassandra 6
theconsensus.dev
theconsensus.dev
What I can say though (as someone running thousands of cpus worth of cassandra at the moment); is that I deeply dislike this database. It's an operational nightmare, and I will not miss it even the slightest bit if it goes away forever.
On the other hand, I'm sure glad to see a bit of life in cassandra dev, it seems to have been dormant for a while; but would I pick it for new applications in 2026? No. I'd strongly recommend against using it unless you have the money to pay for a dedicated team to maintain it, and even then just.. No.
We are using ScyllaDB, but since they discontinued their Open Source version we're stuck on the last supported version, and reading about the operational headaches of Cassandra does not inspire confidence to give it a go.
Mongo bit me a lot pre-wiredtiger and I refused to forgive them for years, but I'm using it again since 8.x and it's really... Boring, Scalable. There are many ways to skin a cat though, and I know not everyone has the luxury of redesigning their apps to fit the persistence layer.
I’d love to use postgres, and have in various times in the past and love it (it never broke) — but one machine isn’t nearly big enough for really any of my current applications.
ydb is not clear if easier to maintain at scale.
I have high hopes for Neki from Planetscale but then again if you are not stuck on Postgres for whatever reason, Vitess with MySQL is about as battle tested as it gets.
Do you think you are missing anything by being on scylla oss?
Also Mongo is catching up in the use case we have and it’s even more scary. We are all the time at the exact edge of Mongo scalability and I’m talking about very good, few-years-invested-in setup on NMVe that is really delicate…
I would not recommend starting new projects with it either, but what else will you use?
I’ve run more Cassandra than anyone on the planet. Also more FoundationDB. And more Postgres than I can count. Likely 3 orders of magnitude more than you.
1. Any db at that scale requires a team. Thousands of cores is gonna be either paying saas or paying a team and I don’t care what the tech is. You’re gonna fuck up any db on the market letting your app eng run a thousand cores of Postgres or MySQL or couchbase or cockroach or tidb.
2. Cassandra at scale has a demonstrably better cost and availability slo than literally annything else I’ve ever tried to run, as long as you have a competent team. And I had a great team. But we had a great team because we understood that at million core scale it’s a core of the product and you invest in your core. But a good team of a dozen people can run a million cores at 6-8 nines, at lower cost per byte or cost per query than any db-aas you can buy online from any cloud vendor. I know this because we checked, and I’ve been ahead every time.
3. The db isnt fun to run. But it’s getting way better. If you think this is 2009, it’s not. The folks working on it in 2026 know what they’re doing and the last decade has made it measurably safer and easier.
Nothings free, but I’d bet my salary I can run damn near any company on Cassandra cheaper than any of your alternatives. Even all the vendors who keep selling against Cassandra. A competent team on Cassandra is going to beat your vendor product 90% of the time.
In just one sentence or two, how would you describe it?
Postgres isn’t the answer for my workload tho we really tried, i even wrote custom sharding for our postgres and it couldn’t handle the writes the cassandra setup shrugs off, but for sure this isn’t a ‘normal’ requirement most applications have.