I noticed that it is possible to build an index on a function to speed
retrieval of data. The example in the docs was a create index on a name
field forced to lower case. Would it be possible to make an index on an
aggregate to speed the return of aggregate info, while keeping it up to
date as the data changes? I know that index maintenance would be HUGE
overhead, but on mostly static data that gets occasional updates, it could
be good.