szehon-ho commented on PR #4898: URL: https://github.com/apache/iceberg/pull/4898#issuecomment-1209652918
@ConeyLiu that's a good question, I think (may be wrong) rewriteDataFiles groups files by partition/partition spec, and may not preserve the old schemas. Ie, all the data files are rewritten with latest schema of that partition spec. I think the situation would be the same even in your proposal to add new schemaid field to data_file, right? After rewriteDataFiles we have to carry over the latest schema-id of each spec , in order for your initial proposed optimization to be accurate? Because there may be data in the new file that was written by a later schema. -- 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] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
