ARROW-3404: [C++] Make CSV chunker faster #2684
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This speeds up multi-threaded CSV reads by removing the serial bottleneck of detecting newlines when no newlines can be present in CSV values. On this machine (8-core AMD processor), the speed of reading a CSV file of text column data goes from 600 MB/s (before this patch) to 1.2 GB/s.
wesm
approved these changes
Oct 2, 2018
| @@ -40,6 +40,8 @@ struct ARROW_EXPORT ParseOptions { | |||
| bool escaping = false; | |||
| // Escaping character (if `escaping` is true) | |||
| char escape_char = '\\'; | |||
| // Whether values are allowed to contain CR (0x0d) and LF (0x0a) characters | |||
| bool newlines_in_values = false; | |||
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I was initially thinking the default for this should be "true", but I would wager > 90% of CSV files do not have embedded newlines and so when someone has such a "special" file they can opt in to this additional logic
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We can change the default anyway, I just thought it would be nice to have nice numbers out of the box :-)
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Very nice speedup! |
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This speeds up multi-threaded CSV reads by removing the serial bottleneck of detecting newlines when no newlines can be present in CSV values.
On this machine (8-core AMD processor), the speed of reading a CSV file of text column data goes from 600 MB/s (before this patch) to 1.2 GB/s.