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Comment by onedev | Hacker News Reader

People still use MongoDB in 2014?

Enough people use it to have the company valued above a billion dollars, have their first MongoDB World (http://world.mongodb.com) and have a HN darling like Stripe as a power user.

Sure, MongoDB has its shortcomings, but so does <Someone's favorite database>. It's much more productive to understand the pros and cons of using it and use it (or not user it) appropriately.

> Sure, MongoDB has its shortcomings, but so does <Someone's favorite database>.

I've been learning Postgres lately and have been liking it so far. What are its shortcomings? Haven't run into something bad about it yet.

No multi-master replication. You can have many read-only slaves replicating a single master, but all your writes have to go to the master, and if the master goes down, you can't write at all until one of the slaves is promoted to become a new master.

There are third-party tools which add multi-master replication, but all seem to suffer from some combination of complexity, flakiness, project deadness, or project immaturity. Postgres-XC seemed the best last time i looked, but it does seem quite complex.

Work is currently underway to bring multi-master replication into core PostgreSQL, under the name "bi-directional replication":

https://wiki.postgresql.org/wiki/BDR_Project

I have no idea if or how this interacts with Postgres-XC. I would imagine the end-game will be that by ~2016, there will be both tightly-coupled (synchronous, immediately consistent, like Postgres-XC) and loosely-coupled (asynchronous, eventually consistent, like BDR) multi-master replication in core PostgreSQL.

That's a long time to wait given that there are noSQL and newSQL databases which have that right now, but when it arrives, it will bring PostgreSQL's huge baggage train of other good stuff with it.

Complexity.

Though it has definitely been improving over the years.

really, what's the point of that comment?

For what it's worth, I think it an interesting question. Considering just how hyped Mongo was a few years ago, and how many other NoSQL databases (CouchDB, Riak, Cassandra perhaps even Postgres with its JSON support) gained mind share since then.

Yeah Mongo was "The Flavor Du Jour" just a couple years ago, with MongoDB articles hitting frontage like every week. Now we don't ever hear about it and people don't really use it much either.

People don't use it because it is terrible. I had to manage a 5-node Mongo cluster as recently as 2 years ago, and I still drink heavily because of it. It was a data roach-motel - your documents check in, but they never check out!!!

Everything ran fine, until it was time to fail over - and the company had a 'full failover every quarter' commitment. Every single time we went from the 2-node primary site to the 3-node secondary, all he would break loose. Bad writes, lost partitions, it was a new 'thing' every quarter. Mongo, in my limited experience, was a terrible platform and I recommend everyone who is thinking of implementing it to run screaming. It accepts data SUPER fast, but so does /dev/null.

I haven't personally used it but I believe there is (was) enough factual technical information to reach this conclusion, including this linked blog post of Kyle's. I was shocked when I read that. Data loss is generally not okay and expected. I'd say most were not aware that the potential for data loss was actually in the design of these products before the Jepsen posts. I believe these flaws impacted most of what people were using it for, so its continued use, particularly on new projects, in the presence of other databases such as Cassandra and Riak is surprising.

And this is not even factoring reports of slow progress, in your face bugs, and PITA manageability.

While it us true substantial progress may have occurred in the less than two years since that test, I would need to see some solid evidence of substantial improvement to consider mongoDB.

That's my outlook based on what I have read.

This is where the MongoDB guys are very sly. MongoDB works brilliantly if you are one developer on one desktop working on one app - you don't need a DBA or any other ops guys, you can just develop away to your little heart's content!

So they write their app and chuck it over the wall to ops, and by then it's a fait accompli, the ops guys know they will look very bad to management if they say "WTF is this?". So they try to make it more-or-less work, then come on HN to share war stories.

Not advocating MongoDB, but I think if we base our opinions solely on how things were 2 years ago, we would end up still basing our opinions on how things were 10 years ago. Software breaks, 'poor' design decisions are made, etc, but at the same time, 2 years is a lot of time for improvements to be made.

My HTML5 app failed me 3 years ago, I've now been recommending that everyone stay away from HTML5. /s

Maybe it's just me, but I don't know if I could ever trust an engineering culture that thought succeed-without-acknowledgement was a good default. At least not as a primary source of truth system. There are plenty of databases that take data seriously and have from the beginning. I'd probably just use one of those.

You realize that was resolved 1.5 years ago, right? Also, it was a driver-level implementation. Comments like this make you sound more troll and less informative.

"Every single time we went from the 2-node primary site to the 3-node secondary" ... Can you explain what this means in terms of MongoDB?

People still use it. Hell, some people love it. I was using it about a year ago as a primary caching layer at the company I worked for then. Given a choice I would have gladly picked something else. Damn near anything else actually. Hope its improved since then.

The one use case MongoDB might be useful for... memcached already did better a decade ago.

Yup. Super big names too like Verizon, Forbes, and the British Government too. So...

I'll wager all of those have more COBOL than they do any other technology. Probably 1000x more than they're running on MongoDB.

Having one small team in a 6 figure sized organization using mongo doesn't mean a single thing, but makes your statement true, which is how most of these flagship customers are able to be advertised.

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