Is the act of *caching* an fq very expensive? (seems to cost 4 seconds in my example)

[Brett Hoerner]

If I run a query like this,

fq=text:lol
fq=created_at_tdid:[1400544000 TO 1400630400]

It takes about 6 seconds. Following queries take only 50ms or less, as
expected because my fqs are cached.

However, if I change the query to not cache my big range query:

fq=text:lol
fq={!cache=false}created_at_tdid:[1400544000 TO 1400630400]

It takes 2 seconds every time, which is a much better experience for my
"first query for that range."

What's odd to me is that I would expect both of these (first) queries to
have to do the same amount of work, expect the first one stuffs the
resulting bitset into a map at the end... which seems to have a 4 second
overhead?

Here's my filterCache from solrconfig:

    <filterCache class="solr.FastLRUCache"
                 size="64"
                 initialSize="64"
                 autowarmCount="32"/>

Thanks.