Regex SerDe doesn't support the serialize() method error

Question

I have a table structure as below.

CREATE TABLE db.TEST(
f1 string,
f2 string,
f3 string)
ROW FORMAT SERDE
  'org.apache.hadoop.hive.serde2.RegexSerDe'
WITH SERDEPROPERTIES (
  'input.regex'='(.{2})(.{3})(.{4})' )
STORED AS INPUTFORMAT
  'org.apache.hadoop.mapred.TextInputFormat'
OUTPUTFORMAT
  'org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat'
LOCATION
  'hdfs://nameservice1/location/TEST';

I tried to insert a record into the table as below.

insert overwrite table db.TEST2 
select '12' as a , '123' as b , '1234' as c ;

While trying to insert data into the table, facing the below error.

Caused by: java.lang.UnsupportedOperationException: Regex SerDe doesn't support the serialize() method at org.apache.hadoop.hive.serde2.RegexSerDe.serialize(RegexSerDe.java:289)

Any idea what is going wrong?

Answer 1

You are using wrong SerDe class. org.apache.hadoop.hive.serde2.RegexSerDe does not support serialization. Look at the source code - serialize method does nothing but throws UnsupportedOperationException exception:

 public Writable serialize(Object obj, ObjectInspector objInspector)
      throws SerDeException {
        throw new UnsupportedOperationException(
          "Regex SerDe doesn't support the serialize() method");
}

And the solution is

to use another SerDe class: org.apache.hadoop.hive.contrib.serde2.RegexSerDe, it can serialize the row object using a format string. Serialize format should be specified in the SERDEPROPERTIES. Look at the source code for more details.

Example of SerDe properties:

WITH SERDEPROPERTIES ( 'input.regex' = '(.{2})(.{3})(.{4})','output.format.string' = '%1$2s%2$3s%3$4s') 

For your table it will be like this:

CREATE TABLE db.TEST(
f1 string,
f2 string,
f3 string)
ROW FORMAT SERDE
  'org.apache.hadoop.hive.contrib.serde2.RegexSerDe'
WITH SERDEPROPERTIES (
  'input.regex'='(.{2})(.{3})(.{4})',
  'output.format.string' = '%1$2s%2$3s%3$4s' )
LOCATION
  'hdfs://nameservice1/location/TEST';