猪铸造/数据类型

Question

我正在尝试将关系转储到 AVRO 文件中，但出现了一个奇怪的错误：

org.apache.pig.data.DataByteArray cannot be cast to java.lang.CharSequence

我不使用DataByteArray（字节数组），请参阅下面的关系描述。

sensitiveSet: {rank_ID: long,name: chararray,customerId: long,VIN: chararray,birth_date: chararray,fuel_mileage: chararray,fuel_consumption: chararray}

即使我进行显式转换，我也会遇到同样的错误：

sensitiveSet = foreach sensitiveSet generate (long) $0, (chararray) $1, (long) $2, (chararray) $3, (chararray) $4, (chararray) $5, (chararray) $6;

STORE sensitiveSet INTO 'testOut2222.avro'
USING org.apache.pig.piggybank.storage.avro.AvroStorage('no_schema_check', 'schema', '{"type":"record","name":"xxxx","namespace":"","fields":[{"name":"rank_ID","type":"long"},{"name":"name","type":"string","store":"no","sensitive":"na"},{"name":"customerId","type":"string","store":"yes","sensitive":"yes"},{"name":"VIN","type":"string","store":"yes","sensitive":"yes"},{"name":"birth_date","type":"string","store":"yes","sensitive":"no"},{"name":"fuel_mileage","type":"string","store":"yes","sensitive":"no"},{"name":"fuel_consumption","type":"string","store":"yes","sensitive":"no"}]}');

已编辑：

我正在尝试定义一个输出模式，它应该是一个包含另外两个元组的元组，即stats:tuple(c:tuple(),d:tuple)。

下面的代码没有按预期工作。它以某种方式产生结构：

stats:tuple(b:tuple(c:tuple(),d:tuple()))

下面是describe产生的输出。

sourceData: {com.mortardata.pig.dataspliter_36: (stats: ((name: chararray,customerId: chararray,VIN: chararray,birth_date: chararray,fuel_mileage: chararray,fuel_consumption: chararray),(name: chararray,customerId: chararray,VIN: chararray,birth_date: chararray,fuel_mileage: chararray,fuel_consumption: chararray)))}

是否可以创建如下结构，这意味着我需要从上一个示例中删除元组 b。

grunt> describe sourceData;
sourceData: {t: (s: (name: chararray,customerId: chararray,VIN: chararray,birth_date: chararray,fuel_mileage: chararray,fuel_consumption: chararray),n: (name: chararray,customerId: chararray,VIN: chararray,birth_date: chararray,fuel_mileage: chararray,fuel_consumption: chararray))}

下面的代码没有按预期工作。

  public Schema outputSchema(Schema input) {
    Schema sensTuple = new Schema();
    sensTuple.add(new Schema.FieldSchema("name", DataType.CHARARRAY));
    sensTuple.add(new Schema.FieldSchema("customerId", DataType.CHARARRAY));
    sensTuple.add(new Schema.FieldSchema("VIN", DataType.CHARARRAY));
    sensTuple.add(new Schema.FieldSchema("birth_date", DataType.CHARARRAY));
    sensTuple.add(new Schema.FieldSchema("fuel_mileage", DataType.CHARARRAY));
    sensTuple.add(new Schema.FieldSchema("fuel_consumption", DataType.CHARARRAY));

    Schema nonSensTuple = new Schema();
    nonSensTuple.add(new Schema.FieldSchema("name", DataType.CHARARRAY));
    nonSensTuple.add(new Schema.FieldSchema("customerId", DataType.CHARARRAY));
    nonSensTuple.add(new Schema.FieldSchema("VIN", DataType.CHARARRAY));
    nonSensTuple.add(new Schema.FieldSchema("birth_date", DataType.CHARARRAY));
    nonSensTuple.add(new Schema.FieldSchema("fuel_mileage", DataType.CHARARRAY));
    nonSensTuple.add(new Schema.FieldSchema("fuel_consumption", DataType.CHARARRAY));


    Schema parentTuple = new Schema();
    parentTuple.add(new Schema.FieldSchema(null, sensTuple, DataType.TUPLE));
    parentTuple.add(new Schema.FieldSchema(null, nonSensTuple, DataType.TUPLE));


    Schema outputSchema = new Schema();
    outputSchema.add(new Schema.FieldSchema("stats", parentTuple, DataType.TUPLE));

    return new Schema(new Schema.FieldSchema(getSchemaName(this.getClass().getName().toLowerCase(), input), outputSchema, DataType.TUPLE));

UDF 的 exec 方法返回：

public Tuple exec(Tuple tuple) throws IOException {    
  Tuple parentTuple  = mTupleFactory.newTuple();
  parentTuple.append(tuple1);
  parentTuple.append(tuple2);

EDIT2（固定）

...
Schema outputSchema = new Schema();
outputSchema.add(new Schema.FieldSchema("stats", parentTuple, DataType.TUPLE));

return new Schema(new Schema.FieldSchema(getSchemaName(this.getClass().getName().toLowerCase(), input), outputSchema, DataType.TUPLE);

return outputSchema;

现在我从 UDF 返回正确的模式，其中所有项目都是 chararray 但是当我尝试将这些项目作为 type: string 存储到 avro 文件中时，我得到了同样的错误：

java.lang.Exception: org.apache.avro.file.DataFileWriter$AppendWriteException: java.lang.ClassCastException: org.apache.pig.data.DataByteArray cannot be cast to java.lang.CharSequence
        at org.apache.hadoop.mapred.LocalJobRunner$Job.runTasks(LocalJobRunner.java:462)
        at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:522)

已解决： 好的，问题是数据没有转换为 UDF 主体内的正确类型 - exec () 方法。看起来它现在可以工作了！

Answer 1

这通常意味着您使用的 UDF 没有保留架构，或者它在某个地方丢失了。我相信 DataByteArray 是不知道真实类型时的后备类型。您可能需要添加种姓来解决此问题，但更好的解决方案是修复任何 UDF 正在删除架构。