On 4/19/14, 6:51 AM, "Ken Krugler" <kkrugler_li...@transpac.com> wrote: > >The code I see seems to be using an FSDirectory, or is there another >layer of wrapping going on here? > > return new NRTCachingDirectory(FSDirectory.open(new File(path)), >maxMergeSizeMB, maxCachedMB);
I was also curious about this subject. Not enough to test anything, but enough to look at the code too. FSDirectory.open picks one of MMapDirectory, SimpleFSDirectory and NIOFSDirectory in that order of preference based on what it thinks your system will support. There¹s still the possibility that the added caching functionality slows down bulk index operations, but setting that aside, it does look like NRTCachingDirectoryFactory is almost always the best choice.