+1 to renaming this. [P]Counter is another option.
On Wed, Mar 23, 2016 at 9:12 AM, Kenneth Knowles <k...@google.com.invalid> wrote: > +1 to considering "metric" / PMetric / etc. > > On Wed, Mar 23, 2016 at 8:09 AM, Amit Sela <amitsel...@gmail.com> wrote: > >> How about "PMetric" ? >> >> On Wed, Mar 23, 2016, 16:53 Frances Perry <f...@google.com> wrote: >> >>> >>>>> Perhaps I'm unclear on what an “Aggregator” is. I assumed that a line >>>>> such as the following: >>>>> >>>>> PCollection<KV<String, Double>> meanByName = >>>>> dataPoints.apply(Mean.<String, Double>perKey()); >>>>> >>>>> …would be considered an Aggregator, since it applies a mean aggregation >>>>> over a window. Is that correct, with respect to the Beam terminology? If >>>>> not, what would an example of an Aggregator be? >>>>> >>>> >>> Ah, we may have some slightly confusing terminology here. >>> >>> In that code snippet you are using a PTransform (Mean.perKey) to combine >>> a PCollection using the Mean CombineFn >>> <https://github.com/apache/incubator-beam/blob/c199f085473cfcd79014d0a022b5ce3fdd4863ec/sdk/src/main/java/com/google/cloud/dataflow/sdk/transforms/Combine.java#L359>. >>> An Aggregator >>> <https://github.com/apache/incubator-beam/blob/211e76abf9ba34c35ef13cca279cbeefdad7c406/sdk/src/main/java/com/google/cloud/dataflow/sdk/transforms/Aggregator.java#L54> >>> takes a CombineFn and applies it continuously within a DoFn. So it's more >>> analogous to a 'counter'. You can see an example of aggregators in >>> DebuggingWordCount >>> <https://github.com/apache/incubator-beam/blob/master/examples/src/main/java/com/google/cloud/dataflow/examples/DebuggingWordCount.java#L129> >>> . >>> >>> We never really used the term *aggregation *to refer to a general set of >>> PTransforms until we started describing things to the community. But it is >>> a useful word, so we've ended up in a bit of confusing state. Maybe we >>> should consider renaming Aggregator? Something like "metric" might be >>> clearer. >>> >>>
