ARROW-12355: [C++] Implement efficient async CSV scanning #10103
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westonpace
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lidavidm
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Apr 23, 2021
| auto source = file->source(); | ||
| auto reader_fut = | ||
| OpenReaderAsync(source, *this, scan_options, internal::GetCpuThreadPool()); | ||
| return GeneratorFromReader(std::move(reader_fut)); |
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Should we go ahead and add readahead here?
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The CSV reader does not support parallel readahead yet. Serial readahead might be redundant since the background generator is pretty much already doing that. I suppose it would give us a bit of pipeline parallelism (allowing us to filter & project while we parse & decode) but at the cost breaking up some of the processing locality (e.g. right now we always parse X, decode X, filter X, project X). I'll run some experiments and see if it has any noticeable effect in either direction.
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Adding serial readahead here did not have any effect on performance.
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ARROW-12355: MakeReadaheadGenerator is needed here for the case where everything is completely synchronous (e.g. cached I/O)
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lidavidm
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May 6, 2021
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A tiny bit of cleanup and combines ARROW-12392 and ARROW-12289 to create a true async CSV format. ~~Keeping in draft until ARROW-12392, ARROW-12289, and ARROW-12386 are resolved.~~ Closes apache#10103 from westonpace/feature/ARROW-12355--c-implement-efficient-async-csv-scanning Authored-by: Weston Pace <weston.pace@gmail.com> Signed-off-by: David Li <li.davidm96@gmail.com>
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A tiny bit of cleanup and combines ARROW-12392 and ARROW-12289 to create a true async CSV format. ~~Keeping in draft until ARROW-12392, ARROW-12289, and ARROW-12386 are resolved.~~ Closes apache#10103 from westonpace/feature/ARROW-12355--c-implement-efficient-async-csv-scanning Authored-by: Weston Pace <weston.pace@gmail.com> Signed-off-by: David Li <li.davidm96@gmail.com>
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A tiny bit of cleanup and combines ARROW-12392 and ARROW-12289 to create a true async CSV format. ~~Keeping in draft until ARROW-12392, ARROW-12289, and ARROW-12386 are resolved.~~ Closes apache#10103 from westonpace/feature/ARROW-12355--c-implement-efficient-async-csv-scanning Authored-by: Weston Pace <weston.pace@gmail.com> Signed-off-by: David Li <li.davidm96@gmail.com>
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A tiny bit of cleanup and combines ARROW-12392 and ARROW-12289 to create a true async CSV format.
Keeping in draft until ARROW-12392, ARROW-12289, and ARROW-12386 are resolved.