Mongo is real distributed and scalable DB, while postgres is single server DB, so main consideration could be if you need to scale beyond single server.
I've been playing with CloudNativePG recently and adding replicas is easy as can be, they automatically sync up and join the cluster without you thinking about it.
Way nicer than the bare-vm ansible setup I used at my last company.
MongDB is basically a pile of JSON in comparison, no matter how much you distribute and scale it.
See https://jepsen.io/analyses for how MongoDB has a tradition of incorrect claims and losing your data.
Distributed databases are not easy. Just saying "it is web scale" doesn't make it so.
1. That PgSQL also has issues in jepsen tests?
2. of any distributed DB which doesn't have jepsen issues?
3. It is configurable behavior for MongoDB: can it lose data and work fast, or work slower and do not lose data. There is no issues of unintentional data loss in most recent(5yo) jepsen report for MongoDB.
Your second point seems to imply that everything has issues, so using MongoDB is fine. But there are various kinds of problems. Take a look at the report for RethinkDB, for example, and compare the issues found there to the MongoDB problems.
RethinkDB doesn't support cross document transactions, problem solved lol
MongoDB defects were, let's say, somewhat more severe
[2.4.3] "In this post, we’ll see MongoDB drop a phenomenal amount of data."
[2.6.7] "Mongo’s consistency model is broken by design: not only can “strictly consistent” reads see stale versions of documents, but they can also return garbage data from writes that never should have occurred. [...] almost all write concern levels allow data loss.
[3.6.4] "with MongoDB’s default consistency levels, CC sessions fail to provide the claimed invariants"
[4.2.6] "even at the strongest levels of read and write concern, it failed to preserve snapshot isolation. Instead, Jepsen observed read skew, cyclic information flow, duplicate writes, and internal consistency violations"
let's not pretend that Mongo is a reliable database please. Fast? likely. But if you value your data, don't use it.
* why you are referring on 12yo reports for very early MongoDB version?
If you wish to have a more recent MongoDB report, Jepsen is available for hire, from what I understand.
On average an AWS availability zone tends to suffer at least one failure a year. Some are disclosed. Many are not. And so that database you are running on a single instance will die.
Question is do you want to do something about it or just suffer the outage.
That being said there are plenty of ways to shard Postgres that are free, e.g. Citus. It's also questionable whether many need sharding. You can go a long way with simply a replica.
Postgres also has plenty of its own strengths. For one, you can get a managed solution without being locked into MongoDB the company.
And history has not been nice to startups like this continuing their products over the long term.
It's why unless it is built-in and supported it's not feasible for most to depend on it.
Microsoft does not make money supporting Citus.