andygrove opened a new issue, #7017:
URL: https://github.com/apache/arrow-rs/issues/7017
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what you are trying to do.**
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I started upgrading Comet to use the latest DataFusion/Arrow and saw that an
effort is being made to remove dict_id from arrow-rs `Field`.
It seems odd that arrow-java has dict_id as part of its field
representation, but we plan to remove it from arrow-rs.
I am not 100% sure but this may be problematic for Comet since we seem to
rely on the dictionary_id when passing arrays between Java and Rust. I did not
write this code and am not yet familiar with it, but in Rust we have:
```rust
let mut dict_id = 0;
let fields = arrays
.iter()
.enumerate()
.map(|(i, array)| match array.data_type() {
DataType::Dictionary(_, _) => {
let field = Field::new_dict(
format!("c{}", i),
array.data_type().clone(),
true,
dict_id,
false,
);
dict_id += 1;
field
}
_ => Field::new(format!("c{}", i), array.data_type().clone(),
true),
})
```
and then in Java:
```java
DictionaryEncoding dictionaryEncoding = vector.getField().getDictionary();
Dictionary dictionary =
dictionaryProvider.lookup(dictionaryEncoding.getId());
```
It will take me some time to get up to speed with how we are using this in
Comet, and if it is needed or not.
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I would like more discussion on this before the field is removed.
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