Reduce indices buffer memory usage in LocalPartition #7939
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velox/exec/LocalPartition.cpp
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| auto numInput = input->size(); | |||
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…or#7939) Summary: In the current code, if we partition N rows with M columns to K partitions, we allocate a buffer of N indices for each partitioned output M columns, so the total memory for these indices is $`O(NMK)`$. In this change we reduce this to $`O(NM)`$ by allocating the indices for each partition with the number of rows in that partition only. Reviewed By: xiaoxmeng Differential Revision: D51984975
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This pull request was exported from Phabricator. Differential Revision: D51984975 |
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This pull request was exported from Phabricator. Differential Revision: D51984975 |
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Conbench analyzed the 1 benchmark run on commit There were no benchmark performance regressions. 🎉 The full Conbench report has more details. |
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Summary: In the current code, if we partition N rows with M columns to K partitions, we allocate a buffer of N indices for each partitioned output M columns, so the total memory for these indices is$O(NMK)$ . In this change we reduce this to $O(NM)$ by allocating the indices for each partition with the number of rows in that partition only.
Differential Revision: D51984975