I'd like to revist a solution to the problem of "deep paging" in Solr, leveraging an HTTP based API similar to how IndexSearcher.searchAfter works at the lucene level: require the clients to provide back a token indicating the sort values of the last document seen on the previous "page". This is similar to the "cursor" model I've seen in several other REST APIs that support "pagnation" over a large sets of results (notable the twitter API and it's "since_id" param) except that we'll want something that works with arbitrary multi-level sort critera that can be either ascending or descending.
SOLR-1726 laid some initial ground work here and was commited quite a while ago, but the key bit of argument parsing to leverage it was commented out due to some problems (see comments in that issue). It's also somewhat out of date at this point: at the time it was commited, IndexSearcher only supported searchAfter for simple scores, not arbitrary field sorts; and the params added in SOLR-1726 suffer from this limitation as well.
I think it would make sense to start fresh with a new issue with a focus on ensuring that we have deep paging which:
- supports arbitrary field sorts in addition to sorting by score
- works in distributed mode