Mrinal Bhattacherjee created SPARK-28733:
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Summary: DataFrameReader of Spark not able to recognize the very
first quote character, while custom unicode quote character is used
Key: SPARK-28733
URL: https://issues.apache.org/jira/browse/SPARK-28733
Project: Spark
Issue Type: Bug
Components: SQL
Affects Versions: 2.3.2
Reporter: Mrinal Bhattacherjee
I have encountered a strange behaviour recently, while reading a CSV file using
DataFrameReader of org.apache.spark.sql package (Spark version 2.3.2). Here is
my spark read code snippet.
_{color:#d04437}val sepChar = "\u00C7" // Ç{color}_
_{color:#d04437}val quoteChar = "\u1E1C" // Ḝ{color}_
_{color:#d04437}val escapeChar = "\u1E1D" // ḝ{color}_
_{color:#d04437}val inputCsvFile =
"<some-local-windows-path>\\input_ab.csv"{color}_
_{color:#d04437}val readDF = sparkSession.read.option("sep", sepChar){color}_
_{color:#d04437}.option("encoding", encoding.toUpperCase){color}_
_{color:#d04437}.option("quote", quoteChar){color}_
_{color:#d04437}.option("escape", escapeChar){color}_
_{color:#d04437}.option("header", "false"){color}_
_{color:#d04437}.option("multiLine", "true"){color}_
_{color:#d04437}.csv(inputCsvFile){color}_
_{color:#d04437}readDF.cache(){color}_
_{color:#d04437}readDF.show(20, false){color}_
Due to some awful data, I'm forced to use some unicode characters as sep
character, quote character, escape character instead of default ones. Below is
my input sample data.
{color:#333333}*Ḝ1ḜÇḜsmithḜÇḜ5Ḝ*{color}
{color:#333333}*Ḝ2ḜÇḜdousonḜÇḜ6Ḝ*{color}
{color:#333333}*Ḝ3ḜÇḜsr,tendulkarḜÇḜ10Ḝ*{color}
Here Ç is field separator, Ḝ is quote character and all the fields values are
wrapped with this custom quote character.
The problem I'm getting is, the first occurance of the quote character is not
getting recognized by Spark somehow. I tried with any charcter other than
Unicode like ` ~ X (alphabet X just for a testing scenario), even default quote
(") as well. It works fine in all the scenarios except when Unicode is used as
quote character. The first occurance of the Unicode quote character is coming
as some non printable character �� , hence the wrap end quote character of the
first field of first record is getting included in data.
Here is the output of df show.
+---+------------+-----+
|id |name |class|
+---+------------+-----+
|��1Ḝ |smith |5 |
|2 |douson |6 |
|3 |sr,tendulkar|10 |
+---+------------+-----+
It happens only for the first field of the very first record. Other quote
characters in this file is being read as expected without any issues. When I
keep an extra empty record at the top of the file, i.e., simply a new line (\n)
at the very first line, the issue doesn't occur. Even, that empty row is not
being considered as an empty record in df as well. Thus my problem gets solved.
But this manipulation cannot be done in the production and hence it is an issue
to be bothered about.
I feel, this is a bug. If it is not, kindly let me know the way to process the
same without getting this issue; or else kindly provide a fix at the earliest.
Thanks in advance.
Best Regards,
Mrinal
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