[Jweb_Guru]

Even for a single query, the optimal query plan changes over time with the distribution of data in the table (and in other tables), as well as things like database load. There literally is not one best query plan, even with perfect information. Also, keep in mind that an abundance of even fake indices like this can have adverse effects on planner results by forcing it to consider more (and therefore, more suboptimal) cases with its limited budget.

[silon3]

And that's why people use NOSQL. It's much more predictable in production use.

[Jweb_Guru]

Er, no. It isn't. NoSQL solutions have exactly the same problems. Most just don't have query planners or statistics capable of understanding how to properly deal with the ever-changing data (and also frequently don't even have the indexing capabilities required to do much more than a single get or set efficiently, anyway--these problems tend to come up with larger queries).