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Comment by schmichael | Hacker News Reader

We used verbose key names and paid for it. We even failed to override _id with a useful primary key. So... not great.

That being said, our data is not completely normalized in PostgreSQL, so it's not a totally unfair comparison.

It may be possible to simulate an apples to apples comparison (small keys in mongo + perfectly normalized pgsql tables), but I'm not sure that would be a useful indicator for real world use cases.

Suffice it to say: repeating your schema in every row/document is going to take more space than not repeating it.

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Oh no doubt, and I think naming conventions is something that takes practice over time in this situation - too verbose leads to 'wasted' space, too little leads to making it near impossible for someone to view the database. Since indexes don't store the key names that does alleviate part of the problem as well.

I tend to leave the default _id in place as it also acts as a 'created_on' timestamp, saving the need to add an additional field.

Thanks for the deck. It's always good to hear about situations that didn't work out well and what can be learned going forward (though I do think you'd have a better experience using the 1.8 branch than you did with 1.4).

The real shame is that this is still something the programmer has to worry about in first place.

When you're a database in 2011 then you should have a damn good reason for asking programmers to space-optimize their identifiers. I can't see such a reason in Mongo really.

Everyone should be upvoting this.

I vaguely remember 10gen brainstorming some ideas for fixing this, but it's a pretty poor design decision for a database you're advertising for use in "Big Data" scenarios. (Not that our measly 120 GB db constitutes big data... but even at Medium Data something as silly as key sizes can have a significant performance impact).

Some/M=most Mongodb client libraries can do this for you. I can see arguments both ways to keep it in the server or keep it in the client library. 10gen does a hell of a job supporting a wide variety of very good client libraries.

How is this related only to MongoDB?

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