[infinispan-dev] Removing batching (transactions) requirement from the Lucene Directory

Context reminder: the Infinispan Lucene Directory requires batching. The reason it's using batching was mostly to find a tradeoff between not too big blob sizes (chunking of larger blocks) and reduce network related blocking invocations, taking advantage of the fact we do know pretty well how Lucene will drive this custom structure and how to use Infinispan.. still the amount of other optimizations we applied over time made actual usage of batching not a frequent operation any more, and I see now some reasons to remove batch usage altogether: - batching requires transactions -> since we can't use some non-transactional operations on a transactional able cache any more, this was enabling auto-commit on the many operations which should not use transactions, and negatively impacting performance. - by using batching (transactions) internally we can't have it participate in an existing transaction (without the perils of nested transactions). - for those cases transactions are not desired, it's slowing down all operations since a cache is now either fully transactional or not at all. By running some simple performance tests it even seems that removing these batch operations actually improved performance a little bit; this might need some more investigation and a better test, but at least it makes me think that performance is not going to drop noticeably if we remove it. WDYT? Sanne