[TruthSHIFT]

The most important thing to understand about NoSQL is when you should use it. For many circumstances, NoSQL isn't the right tool for the job. The key is being able to recognize when it is.

I'm still learning how to determine when I should use NoSQL instead of SQL. My best advice is to carefully consider how to plan on querying your data. If you plan on making complex queries that link multiple relationships, NoSQL is not for you.

[analogic]

Or in a slightly different form, what I'd personally love to always have an answer for: Is there a fast way to do this complex query in reasonable time in rdbms or do we have to force it into NoSQLish solution? (say.. solr)

After I've optimized my query/indexes to get from 60s to like 4s running through usual stuff and trying to not do anything too stupid, how to get it to <200ms? Maybe better question how to structure data so you don't need the complex query?