: The culprit seems to be the merger (frontend) SOLR. Talking to one shard
: directly takes substantially less time (1-2 sec).
...
: >> > > >>facet.limit=500000
Your probably most likeley has very little to do with your caches at all
-- a facet.limit that high requires sending a very large amount of data
over the wire, multiplied by the number of shards, multipled by some
constant (i think it's 2 but it might be higher) in order to "over
request" facet constriant counts from each shard to aggregate them.
the dominant factor in the slow speed you are seeing is most likeley
Network IO between the shards.
-Hoss
