Getting 20 lines of sample data is enough, more confuses the sniffer.
@@ -353,7 +353,7 @@ class CSVFormat(FileFormat):
@classmethod
def _get_sample(cls, file_stream):
file_stream.seek(0)
- sample = '\n'.join(file_stream.read(1024 * 1024 * 5).splitlines())
+ sample = '\n'.join(file_stream.read(1024 * 1024 * 5).splitlines()[:20])
return sample