Hi there,

I am using the gandiva C++ library for processing RecordBatch. I would like
to know how I can apply gandiva::Filter for a RecordBatch so that I can do
some filtering without using the projector.

Since I don't find any documentation for it, I read some source code about
its usage, and here are the test cases I found about its usage:
1)
https://github.com/apache/arrow/blob/967728fe4654e5d53bc0789e64e5a9ba7f27f263/cpp/src/gandiva/tests/filter_test.cc
2)
https://github.com/apache/arrow/blob/967728fe4654e5d53bc0789e64e5a9ba7f27f263/cpp/src/gandiva/tests/filter_project_test.cc

>From my reading, I find it is possible to get a SelectionVector by using
the gandiva::Filter, at the same time, you can use the SelectionVector with
the gandiva::Projector to filter RecordBatch when doing projection. My
questions are:
1) if I don't want to do any projection but simply filtering, what is the
recommended way to do it?
2) I am trying to handle the case like "SELECT * FROM table WHERE blah", is
it recommended to apply filtering without projection in this case or is
there any alternative approach doing it?

Thanks.

Regards,
Yue

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