Alter table on the following external table fails:
CREATE EXTERNAL TABLE IF NOT EXISTS MODULES_1 (
    `ModuleID` string  , 
    `ModuleName` string  ,
    `ContractType` string  ) 
PARTITIONED BY (
    meta_version string,
    year string,
    month string,
    day string) 
ROW FORMAT SERDE 'org.apache.hadoop.hive.contrib.serde2.MultiDelimitSerDe' 
WITH SERDEPROPERTIES ( "field.delim"="\t") 
LOCATION '/tst/raw/comarch/modules/1'tblproperties("skip.header.line.count"="3");
When I try to modify this table using below:
Alter table  MODULES_1 ADD COLUMNS(`OperationType` string)  
FAILED: Execution Error, return code 1 from org.apache.hadoop.hive.ql.exec.DDLTask. Error: type expected at the position 0 of '<derived from deserializer>:<derived from deserializer>:<derived from deserializer>:string' but '<' is found.
I tried it with partition specifications:
Alter table  MODULES_1 PARTITIONS(meta_version,`year`,`month`,`day`) ADD COLUMNS(`OperationType` string)
that also fails.
Please suggest a workwround