+1 to the new metrics design. I strongly favor B as well.
On Wed, Oct 12, 2016 at 10:54 AM, Kenneth Knowles <[email protected]> wrote: > Correction: In my eagerness to see the end of aggregators, I mistook the > intention. Both A and B leave aggregators in place until there is a > replacement. In which case, I am strongly in favor of B. As soon as we can > remove aggregators, I think we should. > > On Wed, Oct 12, 2016 at 10:48 AM Kenneth Knowles <[email protected]> wrote: > >> Huzzah! This is IMO a really great change. I agree that we can get >> something in to allow work to continue, and improve the API as we learn. >> >> On Wed, Oct 12, 2016 at 10:20 AM Ben Chambers <[email protected]> >> wrote: >> >> 3. One open question is what to do with Aggregators. In the doc I mentioned >> >> that long term I'd like to consider whether we can improve Aggregators to >> be a better fit for the model by supporting windowing and allowing them to >> serve as input for future steps. In the interim it's not clear what we >> should do with them. The two obvious (and extreme) options seem to be: >> >> >> >> Option A: Do nothing, leave aggregators as they are until we revisit. >> >> >> Option B: Remove aggregators from the SDK until we revisit. >> >> I'd like to suggest removing Aggregators once the existing runners have >> reasonable support for Metrics. Doing so reduces the surface area we need >> to maintain/support and simplifies other changes being made. It will also >> allow us to revisit them from a clean slate. >> >> >> +1 to removing aggregators, either of A or B. The new metrics design >> addresses aggregator use cases as well or better. >> >> So A vs B is a choice of whether we have a gap with no aggregator or >> metrics-like functionality. I think that is perhaps a bit of a bummer for >> users, and we will likely port over the runner code for it, so we wouldn't >> want to actually delete it, right? Can we do it in a week or two? >> >> One thing motivating me to do this quickly: Currently the new DoFn does >> not have its own implementation of aggregators, but leverages that of >> OldDoFn, so we cannot remove OldDoFn until either (1) new DoFn >> re-implements the aggregator instantiation and worker-side delegation (not >> hard, but it is throwaway code) or (2) aggregators are removed. This >> dependency also makes running the new DoFn directly (required for the state >> API) a bit more annoying. >>
