progval opened a new issue, #5859: URL: https://github.com/apache/arrow-rs/issues/5859
**Is your feature request related to a problem or challenge? Please describe what you are trying to do.** https://parquet.apache.org/docs/file-format/bloomfilter/#file-format mentions two ways to layout Bloom Filters: either write each Bloom Filter after its row group, or write all Bloom Filters at the end; then write pointers to Bloom Filters in the footer. The `parquet` crate opts for writing all Bloom Filters at the end, while computing them while each row group is being written. This means Bloom Filters need to be kept in memory while files are being written, which can take significant space. In my use case, ~4TB of Bloom filters while writing a 20TB table. **Describe the solution you'd like** Either switch to the other layout (interleaved with row groups), provide an option to switch between the two, or allow users to flush when they want to. **Describe alternatives you've considered** Expecting users to close the ArrowWriter from time to time, and opening a new one. This would mitigate the memory usage, but not entirely remove it. When writing in parallel from multiple threads, it also means they need to stagger re-openings when writing many files in parallel in order to avoid spikes in RAM. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
