[jeremymcanally]

His last article was intensely ignorant of MongoDB. I appreciate his attempt to promote his product, but the last one showed that he'd spent about 10 minutes on the Wiki and that's it. Or perhaps he's more informed and conveniently left out a number of things that would have made MongoDB look better. I don't want to cast aspersions, but it wasn't a good argument.

This one does seem to be more informed (and I agree with a lot his criticism of MongoDB here), but it's almost like comparing apples to oranges. Things are done in MongoDB a certain way for a number of reasons (e.g., the query interface doesn't allow certain things in a distributed context that you could probably do with a SQL database). But I think anyone who's done large-scale MongoDB deployments can (or at least should) attest that it works well, but perhaps not as well as other solutions (or as well as it could/will work eventually/whatever).

[smanek]

Can you name some of the mistakes/omissions he made in the last article? It didn't seem too far off my (admittedly extremely limited) experience.

[AndrewO]

In the discussion of the previous article posted a couple of days ago, a lot of people complained that he initially didn't provide source code of the tests or go into details about the Mongo's configuration. Some felt that as someone who's worked with internals of RDBMS's, it wouldn't be fair to compare something he knows intimately with something he just learned and didn't spend any time optimizing.

After he posted the code, others complained that the scenarios didn't have enough multi-table joins (which Mongo would represent as nested objects and, at least in the commenters' opinions, would probably do better than it did). There was also a lot of more detailed technical discussions but I won't try to summarize them:

http://news.ycombinator.com/item?id=2161753

(Note: these opinions aren't my own, just what I got out of the discussion.)

[jeremymcanally]

Yup, (nearly) all of those points are valid.

He could have gotten comparable performance by simply turning of safe writes, but the commenters point out a lot of other problems with his original assertions.