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Comment by altdataseller | Hacker News Reader

I am not very well versed in modern Postgres solutions, but at a certain scale, you need to shard your Postgres databases into separate servers. It is not distributed, at least not without some fancy 3rd party plugins? As a result, your application code gets messy dealing with all these shards.

With Mongo, its distributed by default. And if your data keeps growing, you simply add more nodes without any additional changes in the application code.

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As someone that fairly recently spent many months trying to shard a large mongodb system, this is patently false. Mongodb is not sharded “by default”, and sharding it is a lot of work and comes with a very heavy performance impact.

Yes you need to enable sharding but its provided for you, if you want to enable it is what I meant. And adding shards as well. All configuration options in Mongo - vs you need to do this in a more manual way in Postgres (and change your app code more)

Of course it haa a perf impact - nothing is free.

You can even do live resharding since 5.0.

absolutely true that this is an area of improvement for MongoDB - moving from a "replica set" (a single shard cluster but without the config server cluster) to a sharded cluster can be hard. Atlas does it for you, but even then it can be hard. My info says they are working very hard on this.

Live resharding indeed helps for a sharded cluster that already exists.

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