henrifroese opened a new issue, #9654: URL: https://github.com/apache/arrow-datafusion/issues/9654
### Describe the bug Hey, awesome project! I'm trying to use datafusion to query across 100s of thousands of partitioned parquet files in S3. Partitioning is e.g. `experiment=A/measurement=B/date_id=20230101/file.parquet`. Now say I want to query `SELECT * WHERE experiment='A' and measurement='B' and date_id=20230101`. Depending on what I do I get very different performance: 1. If I first `register_listing_table` with prefix `experiment=A/measurement=B/` and `ListingOptions.with_table_partition_cols` only date_id, and then send query `SELECT * WHERE date_id=20230101` that's very fast. 2. If I just `register_listing_table` without prefix, and `ListingOptions.with_table_partition_cols` specify experiment, measurement, date_id, and send the full query `SELECT * WHERE experiment='A' and measurement='B' and date_id=20230101`, that's very slow. (Still works!) It makes sense to me that the first time, we have to list all files, so (2) is slower. But it's also slower on repeated queries. Afaict the actual filtering happens in https://github.com/apache/arrow-datafusion/blob/cf0f8eececd37f593b811320f89c0edd00fd3945/datafusion/core/src/datasource/listing/helpers.rs#L328 which calls `list_partitions`. I can think of two ways to speed this up: 1. Allow caching a `ListingTable`'s files 2. In `ListingTable`, allow specifying the order of partitioning columns (e.g. in this case `[experiment, measurement, date_id]`), and if specified filters are a prefix of this, use that to only list beyond that prefix. E.g. here that'd lead to only listing files after `experiment=A/measurement=B/`. Do any of these ways already exist and I just didn't find them? Or already have tickets? ### To Reproduce _No response_ ### Expected behavior _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: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
