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Don't use MongoDB

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Re: Don't use MongoDB

#21

Post by wickedchicken »

openmosix wrote: post #13

Well, I worked in Vodafone (and Nokia) in very large (laaarge) projects, serving ~50 milions users. Years ago, no hope for NoSQL, we used MySQL. We hit at least 10/20 bugs, solved by 'hotpatch' from Sun. So? I think as developers we should get used to bugs and patches. Should I write a post "don't use MySQL?". We also hit several bugs in the generational garbage collector. Stop using Java? I don't feel the drama here…

> Should I write a post "don't use MySQL?".

yes

> Stop using Java?

yes

Tongue-in-cheek aside, the author's point is that regardless of its current status, MongoDB has been pushed on a lot of people hungry for performance/simplicity; in that singular pursuit they may be setting themselves up for disaster later on. Most developers have a (perhaps unspoken) assumption that a successful write to a database means that data Will Not Disappear. If Mongo violates this assumption, then either developers' attitudes have to change or they should look at other software to avoid being bitten.

Take something like sockets: by using TCP, I am telling my development environment that I would like an unbroken, sequential stream of traffic to another endpoint. Just as importantly, I would like to be notified if this ever is not the case. If I discovered errors in my TCP stack, I want those fixed pronto because any kind of workaround would be reimplementing the very task TCP is meant to cover -- I might as well write my own sequencing and retransmission logic on top of UDP!

Re: Don't use MongoDB

#22

Post by rshm »

Not sure how MongoDB deals with writes in recent versions. It used to leave everything blindly in control of mmap implementation of OS.

Re: Don't use MongoDB

#23

Post by brainless »

Is there someone here in HN who has used MongoDB with large data sets, high concurrency application? Can someone else share some light? And maybe a more recent version of MongoDB...

Re: Don't use MongoDB

#25

Post by jdagostino »

electic wrote: post #12

We extensively tested this inside Viralheat with a write heavy load of over 30,000 writes per second and basically it failed our test. It is not robust for the analytics world is the conclusion we came to. Though, I hope it gets better one day...it has potential.

what did you end up going with?

Re: Don't use MongoDB

#26

Post by antirez »

I appreciate the "public service" intend of this blog post, however:

1) It is wrong to evaluate a system for bugs now fixed (but you can evaluate a software development process this way, however it is not the same as MongoDB itself, since the latter got fixed).

2) A few of the problems claimed are hard to verify, like subsystems crashing, but users can verify or deny this just looking at the mailing list if MongoDB has a mailing list like the Redis one that is ran by an external company (google) and people outside 10 gen have the ability to moderate messages. (For instance in Redis two guys from Citrusbytes can look/moderate messages, so even if I and Pieter would like to remove a message that is bad advertising we can't in a deterministic way).

3) New systems fails, especially if they are developed in the current NoSQL arena that is of course also full of interests about winning users ASAP (in other words to push new features fast is so important that perhaps sometimes stability will suffer). I can see this myself as even if my group at VMware is very focused on telling me to ship Redis as stable as possible as first rule, sometimes I get pressures about releasing new stuff ASAP from the user base itself.

IMHO it is a good idea if programmers learn to test very well the systems they are going to use with simulations for the intended use case. Never listen to the Hype, nor to detractors.

On the other side all this stories keep me motivated in being conservative in the development of Redis and try avoiding bloats and things I think will ultimately suck in the context of Redis (like VM and diskstore, two projects I abandoned).

Re: Don't use MongoDB

#27

Post by latch »

electic wrote: post #12

We extensively tested this inside Viralheat with a write heavy load of over 30,000 writes per second and basically it failed our test. It is not robust for the analytics world is the conclusion we came to. Though, I hope it gets better one day...it has potential.

What was the problem? Performance? I'm not sure what robust means to other people, but to me it implies crashes and data-issues.

Re: Don't use MongoDB

#28

Post by christkv »

A story from a newly created account by a person nobody can verify is real and asking other people to submit his rant (to gain what? credibility to his story?)

nomoremongo 4 hours ago | link I'd appreciate if someone would submit this story for me. http://pastebin.com/raw.php?i=FD3xe6Jt

What's up with the trolling here. Who are you and what company do you work for that has had all those problems you mentioned ?

Re: Don't use MongoDB

#29

Post by dextorious »

chx wrote: post #9

This rant is completely outdated and it shows: "pre transaction log" "fixed this in 1.8". You realize MongoDB is at 2.0 now and the transaction log was introduced in 1.8, right? Yes, MongoDB had problems but since the transaction log it's pretty good. I have used MongoDB since early 1.3 and I knew what I was doing and we never lost a bit of data. There is a tradeoff -- while MongoDB handled write load easily that a M…

""This rant is completely outdated and it shows: "pre transaction log" "fixed this in 1.8". You realize MongoDB is at 2.0 now and the transaction log was introduced in 1.8, right?""

You do realize that 1.8 vs 2.0 is not eons ago, but just a few months, right? And you do realize that the cavalier-throw-all-caution-to-the-wind development attitude that cause all this problems can and does continue to exist? You don't eliminate that just because you added a transaction log (as late as in 1.6, IIRC).

Also: http://news.ycombinator.com/item?id=3200683

Re: Don't use MongoDB

#30

Post by jonpaul »

I've used MongoDB in production since the 1.4 days. It should be noted that my apps are NOT write heavy. But, many of the author's points can be refuted by using version 2.0.

Regarding the point of using getLastError(), the author is completely correct. But the problem is not so much that MongoDB isn't good, it's that developers start using it and expect it to behave like a relational DB. Start thinking in an asynchronous programming paradigm, and you'll have less problems.

I got bit my MongoDB early on. When my server crashed, I learned real quickly what fsync, journaling, and friends can do. The best thing a dev can do before using MongoDB is to RTFM and understand its implications.

The #1 reason that I used MongoDB, was because of the schema-less models. That's it. Early on in an applications life-cycle, the data model changes so frequently that I find migrations painful and unnecessary.

My two cents, hopefully it helps.

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