Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Never, ever, ever use MongoDB

cryto.net

Post reply on HN
Print view View original

91–100 of 122 posts

Re: Never, ever, ever use MongoDB

#91

Post by rdtsc »

cwyers wrote: post #60
jimbokun wrote: post #46

Earlier quoted context omitted.

The article mentions CouchDB and other schematic-less, document DBS, which should be equally good for prototyping but suck less.

I don't understand why a schemaless database is so great for prototyping. Most of the pain from schema changes is when you have a lot of code or a lot of users depending on an existing schema, so it's hard to change (or at least, hard to change while maintaining uptime). Running ALTER TABLE on a small dataset with almost no users is trivial.

Schemaless is just one aspect the other one is clustering/replication. Not sure about MongoDB but CouchDB has master-less peer to peer replication built in. That is hard to bolt-on later on top of Postgres and other databases. Just saying that is another factor in play, not just schema vs no-schema.

Re: Never, ever, ever use MongoDB

#92

Post by threeseed »

cheald wrote: post #72
joepie91_ wrote: post #50

Earlier quoted context omitted.

This doesn't explain the data loss consequences (remember the client default!), nor was it clearly visible on the download page - you'd have to explicitly look for it. This was the case until as late as 2014: https://web.archive.org/web/20140704182658/http://www.mongod... And again, the 'download' page or README is not sufficient for such a warning, nor is a startup message a reliable place to put it (because of init…

Unacknowleged writes were a bad default. I think everyone with a shred of honesty will happily admit to that. It was certainly in the documentation, in the blog posts, in the startup logs, and in the README for quite a long time. If you missed it, it's probably because you weren't paying attention. Again, there are plenty of good reasons to dislike MongoDB, but this isn't one of them, and harping on it substantially…

Also don't forget that almost every driver ignored the defaults and used acknowledged writes anyway.

Re: Never, ever, ever use MongoDB

#93

Post by bsg75 »

cwyers wrote: post #60
jimbokun wrote: post #46

Earlier quoted context omitted.

The article mentions CouchDB and other schematic-less, document DBS, which should be equally good for prototyping but suck less.

I don't understand why a schemaless database is so great for prototyping. Most of the pain from schema changes is when you have a lot of code or a lot of users depending on an existing schema, so it's hard to change (or at least, hard to change while maintaining uptime). Running ALTER TABLE on a small dataset with almost no users is trivial.

A lot of ALTER angst comes from MySQL where any table alter results in a full table lock and copy. In most other RDBMS, column addition and some type changes are a quick metadata change.

Re: Never, ever, ever use MongoDB

#94

Post by threeseed »

joepie91_ wrote: post #85
threeseed wrote: post #83

Earlier quoted context omitted.

What exactly are you talking about ? Why would I care about having my database broken into or even my data being corrupted for hacks/spikes. The very definition of these is that they are throwaway designed to test an idea before rebuilding in something more suitable. And yes MongoDB is schemaless. That doesn't mean your data is going to automatically corrupt itself. You can just define your schema in some shared libr…

> Why would I care about having my database broken into or even my data being corrupted for hacks/spikes. The very definition of these is that they are throwaway designed to test an idea before rebuilding in something more suitable. No. There's no rule that says a prototype must be thrown away - often, it can be built upon further. See also https://news.ycombinator.com/item?id=9913563 > And yes MongoDB is schemaless.…

Actually following proper Agile process you do throw your prototype away.

And yes you can corrupt PostgreSQL. Change the data types without updating your ORM.

Re: Never, ever, ever use MongoDB

#95

Post by bsg75 »

jqm wrote: post #53

I did the MongoDB class they offer but was always scared to use in production (after reading so many bad experiences). And it's really too bad. I find JSON is just so much more pleasant to deal with than SQL.

Apples and oranges. JSON is a format (Object Notation), SQL is a query language. Some databases support queries of JSON structured data using SQL.

Re: Never, ever, ever use MongoDB

#96

Post by giaour »

stickfigure wrote: post #82
giaour wrote: post #26

Earlier quoted context omitted.

The author is cataloguing some of Mongo's "paper cuts," i.e., issues for which warnings and known workarounds exist but that really make the development experience less pleasant. For MongoDB's actual limitations, read aphyr's Call Me Maybe series.

To be fair, aphyr analyzed Mongo's clustering behavior and found a lot of problems. Which has been a consistent refrain in the series - apparently clustering a datastore is hard. ElasticSearch and RabbitMQ fair poorly as well. Also, it's not like Postgres even tries to offer clustering. So what are you comparing Mongo to? There's no reason to believe that a single-node Mongo instance will be any less reliable than a…

Mongo is actually great for very small datasets. But they sell it as a clustered solution (mongodb.org is currently featuring a giant banner that reads, "Agility, scalability, performance. Pick three"), so it's fair to judge them on that.

Re: Never, ever, ever use MongoDB

#98

Post by rwallace »

PebblesHD wrote: post #75

As a smaller setup that requires far less traffic than a large scale real-time application, what are the draw backs of just using a basic MySQL installation? We've hit over 20k views per day on our internal wiki with no signs of even coming close to any limits with either our hardware or the SQL stack.

MySQL is okay. I still think Postgres is better, but the more severe of the problems MySQL had in its early days have been fixed, and honestly it's good enough for most sites. Certainly it's far better than MongoDb.

Re: Never, ever, ever use MongoDB

#99

Post by stickfigure »

giaour wrote: post #96
stickfigure wrote: post #82

Earlier quoted context omitted.

To be fair, aphyr analyzed Mongo's clustering behavior and found a lot of problems. Which has been a consistent refrain in the series - apparently clustering a datastore is hard. ElasticSearch and RabbitMQ fair poorly as well. Also, it's not like Postgres even tries to offer clustering. So what are you comparing Mongo to? There's no reason to believe that a single-node Mongo instance will be any less reliable than a…

Mongo is actually great for very small datasets. But they sell it as a clustered solution (mongodb.org is currently featuring a giant banner that reads, "Agility, scalability, performance. Pick three"), so it's fair to judge them on that.

I agree, but I'm getting the sense that some people (including the OP) are using the CMM article to claim that Postgres is more reliable. Postgres doesn't have this kind of clustering feature at all. Not a fair comparison.

Re: Never, ever, ever use MongoDB

#100

Post by avinassh »

lemevi wrote: post #4

How would one use Meteor.js without MongoDB though? Are you saying not to use Meteor.js too? I was thinking about maybe toying with the idea of making a fully reactive RethinkDB package for Meteor.js.

Meteor 1.2 will have SQL support [0] (and the discussion [1])

[0] - http://info.meteor.com/blog/whats-coming-in-meteor-12-and-be... [1] - https://news.ycombinator.com/item?id=9811583

Post reply on HN