Getting this issue right counts on SOLR-2654

Can we mark this for Lucene 3.x as well?

We should perhaps even configure this to be used by the example server by default given that the performance impact should be negligible if NRT isn't being used.

This issue [only] needs to add configuration options given NRTCachingDirectoryFactory is in trunk.

Another issue currently is that this will not work with SolrCloud correctly because it is not detected as an FSDir it appears, and so we don't get the index dir, and replication does not work.

Easiest approach for now would be to add a NRTCachingDirectory.getDelegate() call and then also check for that.

Quick patch for the issue of getting the index directory. No new tests, but all existing tests pass.

Here's the final patch that changes the default to NRT and also changes the tests that require an FS dir to use NRT most of the time. Looping adds and soft commits on OS-X, I saw about a 3x performance increase in turnaround time.

All tests pass and I plan on committing shortly.

bulk fixing the version info for 4.0-ALPHA and 4.0 all affected issues have "hoss20120711-bulk-40-change" in comment

rmuir20120906-bulk-40-change

this appears to have been committed and included in 4.0-BETA