[fyrerise]

This is probably not the answer you're looking for, but MongoDB no longer has much technical justification.

Compared to Mysql and Postgres, it does have an out-of-the-box partitioning scheme, which is something, and a reason to use it (although I'm not sure it outweighs the downsides).

Compared to newer cloud databases like Spanner, Citus, or Aurora which scale well but also provide your with ACID guarantees reminiscent of traditional RDMSes ... there's really not much there.

[meritt]

> Compared to Mysql and Postgres, it does have an out-of-the-box partitioning scheme,

Both MySQL and PostgreSQL support out-of-the-box partitioning. Are you referring to sharding?

[fyrerise]

> Both MySQL and PostgreSQL support out-of-the-box partitioning. Are you referring to sharding?

Hopefully it's fairly obvious from the context, but yes, I'm referring to horizontal partitioning [1], or sharding.

---

[1] https://en.wikipedia.org/wiki/Partition_(database)

[meritt]

I didn't feel it was obvious.

The top post on HN right now is about PostgreSQL 10 features, of which the very first feature listed is "Native Partitioning" (and it's not about sharding). Relational databases have been using the term "partitioning" for a very long time so if you're going to compare features across comparable systems, you need to use the correct terminology.

https://dev.mysql.com/doc/refman/5.7/en/partitioning.html

https://www.postgresql.org/docs/9.1/static/ddl-partitioning....

Meanwhile the feature you're referring to is sharding and each of these databases refer to it accordingly:

https://docs.mongodb.com/manual/sharding/

https://wiki.postgresql.org/wiki/Built-in_Sharding (via forks)

https://www.mysql.com/products/cluster/scalability.html (via a separate product)

Let's also keep in mind we're discussing MongoDB which has a very rich history of using misleading benchmarks to showcase their product (e.g. benchmarking the number of requests/sec the server can select() versus the fsync() rate of a RDBMS), so I think it's useful to be extremely clear what we're talking about.

[mrgordon]

Yeah a colleague referred to MongoDB as the best marketed database and he was 100% correct. They’ll make some misleading benchmarks, throw a few conferences, and voila you have something to replace your ol’ RDBMS

My favorite MongoDB moment was when Stripe wrote MoSQL so they could sync Mongo into PostgreSQL so data scientists can do joins and otherwise interpret the data. Now you have a “SQL replacement” and SQL instead of just using SQL!

I can see it for truly self contained records at massive scale but IMO it falls flat as a RDBMS replacement which is how most people probably use it still.

[fyrerise]

Fair enough. When I first read your original comment, I thought that you were being unnecessarily pedantic.

I imagined that by using "partitioning" most people would probably know what I was talking about, but I've been working with MongoDB for a long time, so I probably have some cognitive bias here.

"Sharding" is the more specific/better term, but I'd still say that although more general and possibly ambiguous, partitioning is still roughly correct.

[lackbeard]

Yes, he means what you are calling sharding.

Back in 2004 or 2005 when I first learned about "sharding" it was introduced to me as partitioning.

[vacri]

> Compared to newer cloud databases like Spanner, Citus, or Aurora

There's a lot more help available online for Mongo than any of those. Of course, *SQL has a lot as well.

[bdcravens]

Citus and Aurora ARE *SQL (Postgresql and MySQL)