Is apache arrow.Vector.toArray() zero-copy in JS

Question

Same as title: is toArray() a zero-copy memory cast, in effect? Is there a way to find out this sort of things without asking on forums? Thanks.

Answer 1

Apache arrow supports a number of different languages and I don't see any language tag here. I'm going to assume JavaScript because that is the only language that has a toArray method on something called a Vector. If it is not JavaScript then please let me know.

The answer to your question is maybe. If it is a vector of int, float, time, decimal, or timestamp then it will be zero-copy and it is just returning a window into a private variable in the vector.

Otherwise, if it is a different type, then it performs an actual memory copy.

Source: https://github.com/apache/arrow/blob/abc786099627ef429109da16b9dc768b4efbd866/js/src/visitor/toarray.ts

There is also an arrow user's mailing list user@arrow.apache.org which is probably the place to ask this kind of question for the fastest answer.