Yeah, I wasn't sure if I was supposed to post my questions on this jira or on reference guide, so I ended up posting it on both . Thanks for getting back to me. I have couple of questions related to your post.
1) You mentioned that "The issue here is that it's possible that an out of order version number could persist across commits."
Is the above possible even if I am using optimistic concurrency (http://yonik.com/solr/optimistic-concurrency/) to write documents on Solr?
2) Query subscription is going be critical part of my project and our subscribers won't be able to afford loss of alerts. What can I do to make sure that there is not loss of alerts. As long as I get error message whenever there is failure, I will make sure that my system re-tries/replays indexing that specific document.
3) Do you happen to have any stats about possibility of data loss in Solr. How often does that happen? Are there any best practices that we can follow to avoid it?
4) In general, are stream expressions robust enough to be used in production?
5) Is there any more deep dive documentation about topic(). I would love to know its stats for query volume as big as ours (9-10 million). Or, I would love to know how its working internally.