jiacai2050 opened a new issue, #3356: URL: https://github.com/apache/arrow-rs/issues/3356
**Is your feature request related to a problem or challenge? Please describe what you are trying to do.** <!-- A clear and concise description of what the problem is. Ex. I'm always frustrated when [...] (This section helps Arrow developers understand the context and *why* for this feature, in addition to the *what*) --> The metadata of parquet is placed in the footer, In this design, metadata can be written after the data has been written, which allow for single pass writing. But in current implementation of ArrowWriter, we can only provide WriterProperties in `try_new`, for most fields of WriterProperties this is fine, but not the case for key_value_metadata. key_value_metadata is meant for users to save customized information, for example we can encode some stats in here. This usually means that we need to loop the original data to get stats information, this means we have to loop data twice: 1. First to get the stats information 2. Second to write to parquet If ArrowWriter could provide a way to set key_value_metadata after write all records, then only one loop is need. **Describe the solution you'd like** <!-- A clear and concise description of what you want to happen. --> Add new method in ArrowWriter/SerializedFileWriter to let users set key_value_metadata. **Describe alternatives you've considered** <!-- A clear and concise description of any alternative solutions or features you've considered. --> **Additional context** <!-- Add any other context or screenshots about the feature request here. --> -- 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]
