Optimize delta binary decoder in the case where bitwidth=0#9477
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etseidl wants to merge 2 commits intoapache:mainfrom
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Optimize delta binary decoder in the case where bitwidth=0#9477etseidl wants to merge 2 commits intoapache:mainfrom
etseidl wants to merge 2 commits intoapache:mainfrom
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Not seeing the huge improvement from arrow-cpp, but still a nice speedup, and it doesn't seem to be impacting cases where the optimization can't be used. New benchmarks on my workstation (x86 i7-12700K) comparing main (no_opt) to this branch (opt) And the rest of the binary packed benches Details |
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Currently unknown what impact this optimization will have on the other delta encodings. There could be a good speedup for situations like constant length strings + DELTA_LENGTH_BYTE_ARRAY (think UUIDs or hashes), as well as long runs of the same prefix or long runs of strings with no shared prefix with DELTA_BYTE_ARRAY. |
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Which issue does this PR close?
Rationale for this change
Explore if we can achieve the speedups seen in arrow-cpp (apache/arrow#49296).
What changes are included in this PR?
Adds special cases to the delta binary packed decoder when bitwidth for a miniblock is 0. The optimization avoids relying on previous values to decode current ones.
Are these changes tested?
Yes, tests have been added, as well as new benchmarks.
Are there any user-facing changes?
No