[GitHub] [arrow-datafusion] richox opened a new issue, #2491: Sort-merge join optimization by avoiding too many small batches

[GitBox <gi...@apache.org>]

richox opened a new issue, #2491:
URL: https://github.com/apache/arrow-datafusion/issues/2491

   **Is your feature request related to a problem or challenge? Please describe what you are trying to do.**
   A clear and concise description of what the problem is. Ex. I'm always frustrated when [...] 
   (This section helps Arrow developers understand the context and *why* for this feature, in addition to  the *what*)
   
   currently, sort-merge join creates one temporary record batch for each joined key, which results in many small batches and bad performance.
   
   **Describe the solution you'd like**
   A clear and concise description of what you want to happen.
   
   to achieve better performance, we can only store indices of joined pairs and generate a bigger record batch when the number of stored indices reaches the target batch size.
   
   **Describe alternatives you've considered**
   A clear and concise description of any alternative solutions or features you've considered.
   
   row format with JIT is hopefully a better solution in the joining scenario.
   
   **Additional context**
   Add any other context or screenshots about the feature request here.
   
   fuzzy testing with inner joining 1,000,000 integers:
   the original implementation:
   ```
   real	0m32.045s
   user	0m30.868s
   sys	0m1.136s
   ```
   
   improved implementation:
   ```
   real	0m3.367s
   user	0m2.242s
   sys	0m1.048s
   ```
   


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[GitHub] [arrow-datafusion] yjshen closed issue #2491: Sort-merge join optimization by avoiding too many small batches

[GitBox <gi...@apache.org>]

yjshen closed issue #2491: Sort-merge join optimization by avoiding too many small batches
URL: https://github.com/apache/arrow-datafusion/issues/2491


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