Saurabh Joshi created BEAM-10030:
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Summary: Add CSVIO for Java SDK
Key: BEAM-10030
URL: https://issues.apache.org/jira/browse/BEAM-10030
Project: Beam
Issue Type: New Feature
Components: io-ideas
Reporter: Saurabh Joshi
Apache Beam has TextIO which can read text based files line by line, delimited
by either a carriage return, newline, or a carriage return and a newline. This
approach does not support CSV files which have records that span multiple
lines. This is because there could be fields where there is a newline inside
the double quotes.
This Stackoverflow question is relevant for a feature that should be added to
Apache Beam:
[https://stackoverflow.com/questions/51439189/how-to-read-large-csv-with-beam]
I can think of two libraries we could use for handling CSV files. The first one
is using Apache Commons CSV library. Here is some example code which can use
CSVRecord class for reading and writing CSV records:
{color:#172b4d}{{PipelineOptions options = PipelineOptionsFactory.create();}}
{{Pipeline pipeline = Pipeline.create(options);}}
{{PCollection<CSVRecord> records = pipeline.apply("ReadCSV",
CSVIO.read().from("input.csv"));}}
{{ records.apply("WriteCSV", CSVIO.write().to("output.csv"));}}{color}
Another library we could use is Jackson CSV, which allows users to specify
schemas for the columns:
[https://github.com/FasterXML/jackson-dataformats-text/tree/master/csv]
The crux of the problem is this: can we read and write large CSV files in
parallel? If so, would it be good to have a feature where Apache Beam supports
reading/writing CSV files?
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