Hi All, I have this problem where in Spark Dataframe is having null columns for the attributes from JSON that are not present. A clear explanation is provided below:
*Use case:* Convert the JSON object into dataframe for further usage. *Case - 1:* Without specifying the schema for JSON: records.foreachRDD(new VoidFunction2<JavaRDD<String>, Time>() { private static final long serialVersionUID = 1L; @Override public void call(JavaRDD<String> rdd, Time time) throws Exception { if (rdd.count() > 0) { JavaRDD<String> filteredRDD = rdd.filter(x -> x.length()>0); sqlContext = SQLContextSingleton.getInstance(filteredRDD.context()); DataFrame df = sqlContext.read().json(filteredRDD); df.show(); } } }); In the above code sample, filteredRDD is Strings as JSON Objects. *Sample JSON Record: * {"request_id":"f791e831f71e4918b2fcaebfdf6fe2c2","org_id":"y08e7p9g","queue_id":1234,"disposition":"O","created":"2017-06-02 23:49:10.410","assigned":"2017-06-02 23:49:10.410","final_review_status":"cancel","datetime":"2017-06-02 23:49:10.410"} *Dataframe Output:* <http://apache-spark-user-list.1001560.n3.nabble.com/file/t8407/Screenshot_at_Sep_07_11-36-27.png> *Case - 2:* With specifying the schema for JSON: records.foreachRDD(new VoidFunction2<JavaRDD<String>, Time>() { private static final long serialVersionUID = 1L; @Override public void call(JavaRDD<String> rdd, Time time) throws Exception { if (rdd.count() > 0) { JavaRDD<String> filteredRDD = rdd.filter(x -> x.length()>0); sqlContext = SQLContextSingleton.getInstance(filteredRDD.context()); DataFrame df = sqlContext.read().schema(SchemaBuilder.buildSchema()).json(filteredRDD); df.show(); } } }); In the above code sample, filteredRDD is Strings as JSON Objects. *Schema Definition:* public static StructType buildSchema() { StructType schema = new StructType( new StructField[] { DataTypes.createStructField("request_id", DataTypes.StringType, false), DataTypes.createStructField("org_id", DataTypes.StringType, false), DataTypes.createStructField("queue_id", DataTypes.IntegerType, true), DataTypes.createStructField("owner", DataTypes.StringType, true), DataTypes.createStructField("disposition", DataTypes.StringType, true), DataTypes.createStructField("created", DataTypes.TimestampType, true), DataTypes.createStructField("created_user", DataTypes.StringType, true), DataTypes.createStructField("assigned", DataTypes.TimestampType, true), DataTypes.createStructField("assigned_user", DataTypes.StringType, true), DataTypes.createStructField("notes", DataTypes.StringType, true), DataTypes.createStructField("final_review_status", DataTypes.StringType, true), DataTypes.createStructField("event_tag", DataTypes.StringType, true), DataTypes.createStructField("additional_data", DataTypes.StringType, true), DataTypes.createStructField("datetime", DataTypes.TimestampType, true), DataTypes.createStructField("dc", DataTypes.StringType, true), DataTypes.createStructField("case_id", DataTypes.StringType, true), DataTypes.createStructField("case_status", DataTypes.StringType, true) }); return (schema); } *Sample JSON Record: * {"request_id":"f791e831f71e4918b2fcaebfdf6fe2c2","org_id":"y08e7p9g","queue_id":1234,"disposition":"O","created":"2017-06-02 23:49:10.410","assigned":"2017-06-02 23:49:10.410","final_review_status":"cancel","datetime":"2017-06-02 23:49:10.410"} *Dataframe Output:* <http://apache-spark-user-list.1001560.n3.nabble.com/file/t8407/sample.png> If you see in the above case, when schema is defined I am getting the columns that are not specified in the JSON as null. Any work around on getting the result as expected in the first image(without nulls) using schema? I needed this to perform updates into Kudu table. As the other columns are assigned NULL, they are getting updated into KUDU as null which is not desired. Thanks, Ravi -- Sent from: http://apache-spark-user-list.1001560.n3.nabble.com/ --------------------------------------------------------------------- To unsubscribe e-mail: user-unsubscr...@spark.apache.org