[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Dictionary with repeated values?

The way that dictionary encoding is implemented in C++ (with
DictionaryType, DictionaryArray) is a construct particular to the

At the protocol level, dictionary encoding is a property of field at
some level of a schema tree [1].

The dictionary itself is a record batch with a single field/column [2]

So based on the protocol there is no requirement for uniqueness in the
dictionary. I would say it would be preferable for implementations to
avoid constructing dictionaries with duplicates, though.

- Wes


On Wed, Dec 19, 2018 at 5:51 PM Ben Kietzman <ben.kietzman@xxxxxxxxxxx> wrote:
> Is it legal to create a DictionaryType whose dictionary has repeated
> values?