lance-format / lance-format/lance
Offset overflow errors can be confusing for users
Open
A-encoding
good first issue
- Dominant language
- Rust
- Stars
- 7.1k
- Forks
- 852
- Avg merge
- 3d 18h
- Merged PRs (30d)
- 272
Description
When using binary or string columns a single batch of data cannot contain more than 2GiB of data. Users will either need to use large_binary and large_string or make sure to set a custom batch size when reading this data.
However, the error they run into, an "offset overflow" error, is a panic (not great) and very confusing. It is not obvious that the solution is to reduce the batch size:
thread 'lance_background_thread' panicked at .../arrow-data-52.2.0/src/transform/utils.rs:42:56:
offset overflow
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
thread '<unnamed>' panicked at .../rust/lance-encoding/src/decoder.rs:1267:65:
called `Result::unwrap()` on an `Err` value: JoinError::Panic(Id(12814), ...)
Ideally we should be returning an Err here (not panic) and the message should say something like "Could not create array with more than 2GiB of string/binary data. Please try reducing the batch_size."
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Assessment
This issue has not been assessed yet.