Also put a bitvector cache in from of predicate search fields

[baldersheim]

As predicate search fields have a high fixed cost it is worthwhile to add a bitvector cache in front them with a TTL of .

This is identical to what we have in front of imported fields which also has a high fixed cost.

It should also be considered for range searches to quickly take down the cost of fixed ranges common to most queries. I would guesstimate a day or 2 of work.