stevenzwu commented on code in PR #13936: URL: https://github.com/apache/iceberg/pull/13936#discussion_r2308044773
########## format/spec.md: ########## @@ -1861,6 +1861,12 @@ Java writes `-1` for "no current snapshot" with V1 and V2 tables and considers t Some implementations require that GZIP compressed files have the suffix `.gz.metadata.json` to be read correctly. The Java reference implementation can additionally read GZIP compressed files with the suffix `metadata.json.gz`. +### Schema evolution and writing with old schemas + +Writers should write out all fields with the types specified from the table schema. Inserts or upserts are allowed with an outdated schema (updates must use the latest schema to avoid data loss). Column projection rules are designed so that the table will remain readable even if writers use an outdated schema in these cases. Review Comment: > Inserts or upserts are allowed with an outdated schema (updates must use the latest schema to avoid data loss). this sentence is less clear to me. Can we just say `Writers are allowed with an outdated schema.`? I didn't quite get this part `updates must use the latest schema to avoid data loss`. > Column projection rules are designed so that the table will remain readable even if writers use an outdated schema in these cases. Also can we switch this sentence to the one below? This way, the first paragraph is about write and the second paragraph is about read. -- 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: issues-unsubscr...@iceberg.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For additional commands, e-mail: issues-h...@iceberg.apache.org
