feat: Support RunEndEncoded type in approx_distinct

[mkleen]

Which issue does this PR close?

• Closes Support more types for approx_distinct function #22989

Rationale for this change

• Support the Arrow type RunEndEncoded type for approx_distinct

What changes are included in this PR?

• Enable HLLAccumulator and HllGroupsAccumulator to support RunEndEncoded
• Tests for the non-grouped and grouped path as part of aggregate.slt

Are these changes tested?

Yes.

Are there any user-facing changes?

Yes, approx_distinct supports now RunEndEncoded but no breaking changes.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.59%. Comparing base (141663e) to head (9bfac5f).

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #25951      +/-   ##
==========================================
- Coverage   82.59%   82.59%   -0.01%     
==========================================
  Files        1145     1145              
  Lines      443932   443933       +1     
  Branches   443932   443933       +1     
==========================================
- Hits       366663   366656       -7     
- Misses      55012    55017       +5     
- Partials    22257    22260       +3     

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[nuno-faria]

Thanks @mkleen.

The is_supported_type reminded me that we don't do the same thing for lists, maps, ... So approx_distinct does not work for (e.g.) floats but works for list of floats. I think it's something we should look at in a follow up.

[mkleen]

Thanks @mkleen.

The is_supported_type reminded me that we don't do the same thing for lists, maps, ... So approx_distinct does not work for (e.g.) floats but works for list of floats. I think it's something we should look at in a follow up.

Thanks for the review @nuno-faria

I agree, the container types such as lists, maps need another iteration. Technically the only unsupported types for approx_distinct are Float16, Float32 and Float64. DuckDB supports them. So maybe it's worth thinking to support them in datafusion as well.

[jayzhan211]

Thanks @mkleen @nuno-faria !