Pig:UDF 没有返回预期的结果集
Pig: UDF not returning expected resultset
这是我正在处理的示例数据:
Peter Wilkerson 27 M
James Owen 26 M
Matt Wo 30 M
Kenny Chen 28 M
我创建了一个简单的 UDF
来像这样过滤年龄:
public class IsApplicable extends FilterFunc {
@Override
public Boolean exec(Tuple tuple) throws IOException {
if(tuple == null || tuple.size() > 0){
return false;
}
try {
Object object = tuple.get(0);
if(object == null){
return false;
}
int age = (Integer)object;
return age > 28;
} catch (Exception e) {
throw new IOException(e);
}
}
}
这是我用于使用此 UDF 的脚本:
records = LOAD '~/Documents/data.txt' AS (firstname:chararray,lastname:chararray,age:int,gender:chararray);
filtered_records = FILTER records BY com.udf.IsApplicable(age);
dump filtered_records;
转储不显示任何记录。请让我知道我错过了什么。
tuple.size() > 0
条件是 if stmt
中的 always true
,因此它永远不会进入 try block(ie filtering logic)
,这就是您得到空结果的原因。你能这样改变if条件吗?
System.out.println("TupleSize="+tuple.size());
if(tuple == null || tuple.size() < 0){
return false;
}
控制台中的示例调试输出:
2015-02-13 07:40:46,994 [Thread-2] INFO org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapOnly$Map - Aliases being processed per job phase (AliasName[line,offset]): M: records[3,10],records[-1,-1],filtered_records[4,19] C: R:
TupleSize=1
TupleSize=1
TupleSize=1
这将为所有行返回 false
:
if (tuple == null || tuple.size() > 0) {
return false;
}
这是获取 userName
而不是 age
:
Object object = tuple.get(0);
这是我正在处理的示例数据:
Peter Wilkerson 27 M
James Owen 26 M
Matt Wo 30 M
Kenny Chen 28 M
我创建了一个简单的 UDF
来像这样过滤年龄:
public class IsApplicable extends FilterFunc {
@Override
public Boolean exec(Tuple tuple) throws IOException {
if(tuple == null || tuple.size() > 0){
return false;
}
try {
Object object = tuple.get(0);
if(object == null){
return false;
}
int age = (Integer)object;
return age > 28;
} catch (Exception e) {
throw new IOException(e);
}
}
}
这是我用于使用此 UDF 的脚本:
records = LOAD '~/Documents/data.txt' AS (firstname:chararray,lastname:chararray,age:int,gender:chararray);
filtered_records = FILTER records BY com.udf.IsApplicable(age);
dump filtered_records;
转储不显示任何记录。请让我知道我错过了什么。
tuple.size() > 0
条件是 if stmt
中的 always true
,因此它永远不会进入 try block(ie filtering logic)
,这就是您得到空结果的原因。你能这样改变if条件吗?
System.out.println("TupleSize="+tuple.size());
if(tuple == null || tuple.size() < 0){
return false;
}
控制台中的示例调试输出:
2015-02-13 07:40:46,994 [Thread-2] INFO org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapOnly$Map - Aliases being processed per job phase (AliasName[line,offset]): M: records[3,10],records[-1,-1],filtered_records[4,19] C: R:
TupleSize=1
TupleSize=1
TupleSize=1
这将为所有行返回 false
:
if (tuple == null || tuple.size() > 0) {
return false;
}
这是获取 userName
而不是 age
:
Object object = tuple.get(0);