sriharshaj commented on PR #12634: URL: https://github.com/apache/iceberg/pull/12634#issuecomment-3618682224
> I was checking this mechanism lately and I think there are 2 parts in the story. First, Spark computes "needed" schema and can prune schema by different optimization rules. Then it passes this schema to Iceberg level and then there is additional PruneColumns logic that Iceberg doing, in which Iceberg trying to take file schema and needed schema(computed by spark) and decide what columns from parquet(e.g.) to read(by judging if needed schema is sound with file schema etc). I.e. IO pruning depends on the later logic, but it takes into account what Spark computed Yeah, that sounds right. Optimizations on the Spark side may not be applied when reading the data from Parquet. -- 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]
