Thanks for your reply!
- Combining the language indices may be a good approach since we have to support 10 different languages (which is a limited number) and we can legitimately expect that 90% of the documents are in one language).
- I wouldn't use weekly indices since 90 percent of queries are on the data from the last two days. Why should I keep 5 days data unnecesseraly? Wouldn't slow down the system, would it?
- Combining types seems to be also not a good approach since we'll have at least 4 different types, and we know that dispersion between types are 2/3 1/6 1/6 and for the fourth type is unknown.