2010YOUY01 opened a new issue, #16131: URL: https://github.com/apache/datafusion/issues/16131
### Is your feature request related to a problem or challenge? Part of https://github.com/apache/datafusion/issues/16065 Note: some steps are not related spilling execution, but they're very related general optimization, so I also mentioned them here. ## Background In sort queries, when the sort key is multiple columns, a row format can be used to accelerate comparison. See more about the background in: https://arrow.apache.org/blog/2022/11/07/multi-column-sorts-in-arrow-rust-part-1/ https://duckdb.org/pdf/ICDE2023-kuiper-muehleisen-sorting.pdf ## Current status Row format is used in the sort-preserving merge executor to speed up comparison among multiple merge inputs, but not used in the sort executor. Note: probably its better to help get https://github.com/apache/datafusion/pull/15380 merged first, then start the following steps. ## Purposed next steps 1. Use row format by default in the sort executor. This may temporarily slow down end-to-end benchmarks, but performance can be recovered through future optimizations (see the next point). This change also resolves [issue #14748](https://github.com/apache/datafusion/issues/14748). 2. A sort query executed across multiple partitions currently goes through two stages of SPM: `Local Sort -> SPM1 -> SPM2`. At each stage, the Arrow Row Format array is repeatedly converted without reuse. We should pass the converted rows downstream to enable reuse and reduce overhead. 3. For further optimization in workloads with nearly sorted input, the converted rows can be used to compute each local sort batch’s min/max. This can help concatenate batches without gaps and reduce the degree of merging needed. 4. For further optimization in memory-limited sorts, the converted rows can be written to the spill file and reused when reading back, improving efficiency. ### Describe the solution you'd like _No response_ ### Describe alternatives you've considered _No response_ ### Additional context _No response_ -- 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: github-unsubscr...@datafusion.apache.org.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For additional commands, e-mail: github-h...@datafusion.apache.org
