Just Pushed: Close and Open an index

Hi,

Just pushed support for closing and opening an index. Closing an index
results in the index having almost no overhead on the cluster (except for
maintaing its metadata). For this to happen, there has been a round
of enhancements in elasticsearch, where if a node does not have a shards for
a specific index allocated on it, it also closes that index (not metadata),
which include parsed mappings, analyzers and other index level constructs.
These enhancements, of course, apply for open indices as well, if a node has
no shards for a specific index allocated on it.

The fact that an index is closed is maintained across cluster restarts. A
closed index will remain closed post full cluster restart. The state of an
index (closed or opened) is exposed in the cluster state API. A closed index
has no shards hence no shards allocation, so it will not be seen in the
routing table.

The issue is here:
http://github.com/elasticsearch/elasticsearch/issues/issue/447.

cheers,
-shay.banon