Hive table from CSV. The line termination in quotes

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梦毁少年i
梦毁少年i 2021-01-13 14:54

I try to create table from CSV file which is save into HDFS. The problem is that the csv consist line break inside of quote. Example of record in CSV:



        
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  • 2021-01-13 15:30

    There is right now no way to handle multilines csv in hive directly. However, there is some workaround:

    1. produce a csv with \n or \r\n replaced with your own newline marker such <\br>. You will be able to load it in hive. Then transform the resulting text by replacing the latter by the former

    2. use spark, it has a multiline csv reader. This works out the box, while the csv beeing not read in a distributed way.

      val df = spark.read
      .option("wholeFile", true)
      .option("multiline",true)
      .option("header", true)
      .option("inferSchema", "true")
      .option("dateFormat", "yyyy-MM-dd")
      .option("timestampFormat", "yyyy-MM-dd HH:mm:ss")
      .csv("test.csv")
      .write.format("orc")
      .saveAsTable("myschma.myTable")
      
    3. use an other format such parquet, avro, orc, sequence file, instead of a csv. For example you could use sqoop to produce them from a jdbc database. Or you could write your own program in java or python.

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  • 2021-01-13 15:35

    I found the solution. You can define your own InputFormatter. Then the DDL for HQL table will looks like this (At first you need to add your custom jar file):

    ADD JAR /path/to/your/jar/CSVCustomInputFormat.jar;
    DROP TABLE hive_database.hive_table;
    CREATE EXTERNAL TABLE  hive_database.hive_table
    (   
        ID STRING,
        PR_ID STRING,
        SUMMARY STRING 
    )
    ROW FORMAT SERDE 'org.apache.hadoop.hive.serde2.OpenCSVSerde'
    WITH SERDEPROPERTIES (
       "separatorChar" = ",",
       "quoteChar"     = "\"",
       "escapeChar"    = "\\"
    ) 
    STORED AS 
    INPUTFORMAT 'com.hql.custom.formatter.CSVCustomInputFormatt' 
    OUTPUTFORMAT 'org.apache.hadoop.hive.ql.io.orc.OrcOutputFormat' 
    LOCATION '/path/to/hdfs/dir/csv'
    tblproperties('skip.header.line.count'='1');
    

    Then how to create the custom input formatter you can see for example here: https://analyticsanvil.wordpress.com/2016/03/06/creating-a-custom-hive-input-format-and-record-reader-to-read-fixed-format-flat-files/

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