Devs, (This discussion is somewhat of a spinoff of our previous recent conversation about HTrace, but I'd like to narrow the discussion to one specific topic regarding our tracer service.)
I'd like to remove Accumulo's tracer service and corresponding presentations in the monitor for 2.0. The tracer service currently acts as a sink for the traces from Accumulo. While there is interest in tracing Accumulo, and Accumulo may itself be suitable (with the right schema) for storing traces, I do not think acting as a "trace sink" is really the kind of thing we should be doing as part of Accumulo's out-of-the-box core functionality. Also, the presentation and search capabilities of the traces found in the trace table (by convention, and assumed by the monitor) is far from an ideal presentation of this data, and I don't think the Accumulo project should continue maintaining that inside the core project's monitor, either. I think we should encourage interested volunteers to contribute to other trace presentation software (wherever they may exist) any necessary "backing store" implementation based on Accumulo. None of this would remove tracing instrumentation from Accumulo... it would just require users interested in trace data from Accumulo to configure an appropriate sink to collect that data in some other integrated component of their overall architecture. Decoupling the integrated trace sink from the instrumentation in Accumulo like this could even be a step towards providing support for multiple different tracing libraries. (I guess we could do this now, but it would be easier if we were not also trying to provide a sink implementation for one specific version of one specific instrumentation library.) Thoughts?
