* Coerce COMPLEX to number in numeric aggregators.
PR #15371 eliminated ObjectColumnSelector's built-in implementations of
numeric methods, which had been marked deprecated.
However, some complex types, like SpectatorHistogram, can be successfully coerced
to number. The documentation for spectator histograms encourages taking advantage of
this by aggregating complex columns with doubleSum and longSum. Currently, this
doesn't work properly for IncrementalIndex, where the behavior relied on those
deprecated ObjectColumnSelector methods.
This patch fixes the behavior by making two changes:
1) SimpleXYZAggregatorFactory (XYZ = type; base class for simple numeric aggregators;
all of these extend NullableNumericAggregatorFactory) use getObject for STRING
and COMPLEX. Previously, getObject was only used for STRING.
2) NullableNumericAggregatorFactory (base class for simple numeric aggregators)
has a new protected method "useGetObject". This allows the base class to
correctly check for null (using getObject or isNull).
The patch also adds a test for SpectatorHistogram + doubleSum + IncrementalIndex.
* Fix tests.
* Remove the special ColumnValueSelector.
* Add test.
* Add SpectatorHistogram extension
* Clarify documentation
Cleanup comments
* Use ColumnValueSelector directly
so that we support being queried as a Number using longSum or doubleSum aggregators as well as a histogram.
When queried as a Number, we're returning the count of entries in the histogram.
* Apply suggestions from code review
Co-authored-by: Victoria Lim <vtlim@users.noreply.github.com>
* Fix references
* Fix spelling
* Update docs/development/extensions-contrib/spectator-histogram.md
Co-authored-by: Victoria Lim <vtlim@users.noreply.github.com>
---------
Co-authored-by: Victoria Lim <vtlim@users.noreply.github.com>
Gian Merlino
Adarsh Sanjeev
Karan Kumar
Ben Sykes