
Dynamo vs. Cassandra: Systems Design of NoSQL Databases (2018) - amortize
https://sujithjay.com/data-systems/dynamo-cassandra/
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etaioinshrdlu
This is the key idea behind these databases. It is a good way to design a hash
table to scale seamlessly.
[https://en.wikipedia.org/wiki/Consistent_hashing](https://en.wikipedia.org/wiki/Consistent_hashing)

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tyingq
I suppose interest in this is rising since AWS just announced managed
Cassandra.

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tlunter
I didn't see if there was a re:invent talk about it, but is it actuallly
Cassandra under the hood? It seemed like it might just be the Cassandra API
akin to Aurora being MySQL.

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tyingq
It happens to be Cassandra, but that did make me think about the way Amazon
brands the Postgres compatible Aurora as "Aurora PostgreSQL".

That's pretty lousy of them to take advantage of the name. I imagine the
uptake would be lower if it weren't in the name, and they had to settle for
just saying "Postgres Compatible" in the description.

I also imagine AWS would come after me if I launched "XYZ Fargate" or similar.

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scarface74
There are two separate offerings. AWS offers Aurora/Postgres which is a fork
of Postgres with Amazon’s own code and there is regular RDS/Postgres which is
basically managed Postgres.

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tyingq
I'm not talking about RDS.

I'm talking about "Amazon Aurora PostgreSQL". That's what they call it. See
this page, for example:
[https://aws.amazon.com/quickstart/architecture/aurora-
postgr...](https://aws.amazon.com/quickstart/architecture/aurora-postgresql/)

As mentioned, they likely wouldn't tolerate a "Tyingq Typhoon Fargate" that
was my Fargate clone.

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scarface74
It _is_ Postgres. It’s using the same source code as a base and it’s
compatible with all Postgres tools.

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tyingq
The storage backend isn't Postgres, and I assume the repeated use of the words
"compatible" and "wire protocol" is on purpose, so they can continue to change
it.

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scarface74
Who cares about the “storage backend”? How does that affect clients?

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meddlepal
Clients no, but if you have had a Postgres DBA optimize your database to take
advantage of known Postgres storage backend behavior you may be in for
unexpected performance degradation under the assumption "it's just Postgres".

That said, I dust that's pretty uncommon.

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scarface74
Well, you get the same problem if you have “network administrators” who took
one AWS certification and call themselves “AWS Consultants”.

In both cases you end up with suboptimal solutions. The lesson to learn is not
that AWS shouldn’t be making storage optimizations, it’s that you don’t depend
on a bunch of old school net ops “lift and shifters” who didn’t take the time
to learn the environment and who think that the cloud is just an overpriced
colo.

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alexnewman
Yearly reminder dynamo != dymanodb

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snypox
Hmm, looks like Dynamo is a storage system. Interesting, never heard about it
before.

[https://en.wikipedia.org/wiki/Dynamo_(storage_system)](https://en.wikipedia.org/wiki/Dynamo_\(storage_system\))

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ripvanwinkle
In the last write wins mechanism if two writes (V1 and V2) happen concurrently
to different replicas why is V2 considered the last write in the article.

Reading the explanation and lead up, i was left with the impression that the
last updates to each column (for a columnar store like Cassandra) would take
effect so the final would be

{"street" : "Cubbon", "city" : "Bombay"}

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FpUser
Is it just me having inadequate vision or the visual design of the article is
challenging? Light grey text on white background, dark red and blackish colors
on dark grey background.

