Rich-T-kid commented on PR #24227: URL: https://github.com/apache/datafusion/pull/24227#issuecomment-5281381819
> If I understand correctly the goal is to evaluate filters during filter pushdown against dictionary / RLE encoded columns? no not exactly. The goal of this PR is to keep RLE parquet columns in their compacted form by materializing them as dictionary arrays instead of regular strings. > We can't propagate these dynamic type changes to the rest of the query plan / scan. Is that right? exactly! This is why it needs to be done as early in the plan as possible. we inspect `DFParquetMetadata::fetch_schema` to see if any RLE columns exist, if so change the plan type from `utf8/binary` to `dict<_,utf8/binary>`. Thanks to some plumbing in arrow-rs it will handle the conversions correctly returning a dictionary array. [this can make reads 60x faster](https://github.com/apache/arrow-rs/pull/1180) -- 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]
