I (perhaps obviously) don't agree that I'm tying myself to old CouchDB or failing to embrace FDB. FDB is a toolkit and does not, to my mind, force us down any particular path.
I haven't sat down to modify couch_views in the manner I've suggested (where ebtree is used as designed; being fed the output of the emit() calls and calculating reductions as it does so) but I think it's a worthwhile exercise. I'd be surprised if performance of map-only traversals would be disappointing but who knows? I also expect it would allow for significant simplification of the code, which is one of the higher virtues. Adam, can you describe in a little more detail how you picture "b+tree is only used for incremental aggregations,"? It's implied in your reply that it would preserve the "interesting property" of keeping user data out of FDB Keys (for casual readers: the new native database encryption, called "aegis", only encrypts the FDB value. It can't encrypt the key as this would change the order of keys, which the current code depends on). Did I misread you? B. > On 23 Jul 2020, at 20:11, Adam Kocoloski <kocol...@apache.org> wrote: > > OK thanks for the clarification. As I said I wasn’t all that confident I > understood the design :) > > I like the idea that the b+tree is only used for incremental aggregations, > rather than storing the entire materialized view, for the same reasons that > Garren stated. > > An index maintained entirely in ebtree has the interesting property that it > does not leak any user data into FDB Keys, which could be attractive for > security reasons. > > Adam > >> On Jul 23, 2020, at 1:54 PM, Garren Smith <gar...@apache.org> wrote: >> >> On Thu, Jul 23, 2020 at 6:55 PM Paul Davis <paul.joseph.da...@gmail.com> >> wrote: >> >>>> I would like to keep ebtree to use just for the reduce index. >>> >>> Could you expand on your reasoning here, Garren? I haven't done any >>> experiments on my own to understand if I'm missing something >>> important. My initial reaction is to not diverge too far from the >>> previous shape of the implementation since we have a decent idea of >>> how that behaves already but perhaps you've seen or measured something >>> I'm not thinking of? >>> >> >> I think this must have been a misunderstanding on my part. I always thought >> of using ebtree to solve reduce and wasn't planning to use it for the map >> index. >> I don't like the idea that we have ordered distributed key/value store and >> then implementing a b-tree on top of that for indexing. Especially since we >> know that the current map index is fast, >> easy to use, and follows recommended practices in the FDB community on how >> to do indexing. ebtree makes sense for reduce and is a means to an end to >> give us CouchDB's reduce api, which is heavily reliant on a b-tree, with >> CouchDB on FDB. This feels like a step backward and I worry we are tying >> ourselves heavily to old CouchDB instead of using the fact that we moving >> to FDB which then allows us to design new api's and functionality. >
