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Andrew Lamb resolved ARROW-11030. --------------------------------- Resolution: Fixed Issue resolved by pull request 9070 [https://github.com/apache/arrow/pull/9070] > [Rust] [DataFusion] HashJoinExec slow with many batches > ------------------------------------------------------- > > Key: ARROW-11030 > URL: https://issues.apache.org/jira/browse/ARROW-11030 > Project: Apache Arrow > Issue Type: Bug > Components: Rust - DataFusion > Reporter: Andy Grove > Assignee: Daniël Heres > Priority: Major > Labels: pull-request-available > Fix For: 3.0.0 > > Time Spent: 7h 40m > Remaining Estimate: 0h > > Performance of joins slows down dramatically with smaller batches. > The issue is related to slow performance of MutableDataArray::new() when > passed a high number of batches. This happens when passing in all of the > batches from the build side of the join and this happens once per build-side > join key for each probe-side batch. > It seems to get exponentially slower as the number of arrays increases even > though the number of rows is the same. > I modified hash_join.rs to have this debug code: > {code:java} > let start = Instant::now(); > let row_count: usize = arrays.iter().map(|arr| arr.len()).sum(); > let num_arrays = arrays.len(); > let mut mutable = MutableArrayData::new(arrays, true, capacity); > if num_arrays > 0 { > debug!("MutableArrayData::new() with {} arrays containing {} rows took {} > ms", num_arrays, row_count, start.elapsed().as_millis()); > } {code} > Batch size 131072: > {code:java} > MutableArrayData::new() with 4584 arrays containing 3115341 rows took 1 ms > MutableArrayData::new() with 4584 arrays containing 3115341 rows took 1 ms > MutableArrayData::new() with 4584 arrays containing 3115341 rows took 1 ms > {code} > Batch size 16384: > {code:java} > MutableArrayData::new() with 36624 arrays containing 3115341 rows took 19 ms > MutableArrayData::new() with 36624 arrays containing 3115341 rows took 16 ms > MutableArrayData::new() with 36624 arrays containing 3115341 rows took 17 ms > {code} > Batch size 4096: > {code:java} > MutableArrayData::new() with 146496 arrays containing 3115341 rows took 88 ms > MutableArrayData::new() with 146496 arrays containing 3115341 rows took 89 ms > MutableArrayData::new() with 146496 arrays containing 3115341 rows took 88 ms > {code} > > > > > -- This message was sent by Atlassian Jira (v8.3.4#803005)