[erlang-questions] Speed of CSV parsing: how to read 1M of lines in 1 second

Gordon Guthrie <>
Fri Mar 23 13:54:00 CET 2012


Max

There is a csv parser for RFC 4180 compliant csv files which is now
being maintained by Eric Merritt:
https://github.com/afiniate/erfc_parsers/tree/master/src

Gordon

On 23 March 2012 10:30, Max Lapshin <> wrote:
> I need to load large CSV file into memory very fast.
>
> I've tried to use erlang parser, but my results were very bad (in fact
>  file:read_line is very slow), so I've tried to make a NIF for it.
> Target speed is 1 microsecond per line.
>
>
> My CSV has very strict format: only numbers, no quoting, \n in the
> end. Also I moved parsing of integers and date into NIF.
>
> My results are here: http://github.com/maxlapshin/csv_reader and I get
> only 15 microseconds:  4,5 seconds for 300K lines CSV.
>
> Currently I use fgets to read line by line from file. Maybe it is a
> bad idea and I should use mmap or implement 1MB buffer for read?
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-- 
Gordon Guthrie
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