perf: decimal decode improvements #727
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@parthchandra The |
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@andygrove @kazuyukitanimura this is ready for review. |
viirya
approved these changes
Jul 31, 2024
| target[..source.len()].copy_from_slice(source) | ||
| // Originally `target[..source.len()].copy_from_slice(source)` | ||
| // We use the unsafe copy method to avoid some expensive bounds checking/ | ||
| unsafe { std::ptr::copy_nonoverlapping(source.as_ptr(), target.as_mut_ptr(), source.len()) } |
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copy_from_slice is copy_nonoverlapping with the if self.len() != src.len() check.
Do you have any benchmark results to show the difference by any chance?
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Before this
scan decimal (spark) : 1.0x
scan decimal (Comet, decimal 128) : 0.4x
After
scan decimal (Comet, decimal 128) : 0.5x
So a small improvement.
andygrove
approved these changes
Aug 1, 2024
himadripal
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to himadripal/datafusion-comet
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Sep 7, 2024
* Add scan only micro benchmark query * Use int32 column reader for decimals with precision less than 9 * Use 'copy_nonoverlapped' in memcpy * format * Revert int32columnreader changes (cherry picked from commit 2318a8e)
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Which issue does this PR close?
Part of #679 and #670
.
Rationale for this change
profiler output shows that with decimal128 enabled we have a bottleneck in
comet::common::bit::memcpy.What changes are included in this PR?
This PR changes the method to use
copy_nonoverlappedfor speedHow are these changes tested?
Tested using existing tests. This is a draft PR partly to verify there are no regressions.