hive can't create table with nested avro schema - hive

Question

I'm trying to use a nested avro schema to create a hive table. But it does not work. I'm using hive 1.1 in cdh5.7.2.
here is my nested avro schema:
[
{
"type": "record",
"name": "Id",
"namespace": "com.test.app_list",
"doc": "Device ID",
"fields": [
{
"name": "idType",
"type": "int"
},{
"name": "id",
"type": "string"
}
]
},
{
"type": "record",
"name": "AppList",
"namespace": "com.test.app_list",
"doc": "",
"fields": [
{
"name": "appId",
"type": "string",
"avro.java.string": "String"
},
{
"name": "timestamp",
"type": "long"
},
{
"name": "idList",
"type": [{"type": "array", "items": "com.test.app_list.Id"}]
}
]
}
]
And my sql to create table:
CREATE EXTERNAL TABLE app_list
ROW FORMAT SERDE
'org.apache.hadoop.hive.serde2.avro.AvroSerDe'
STORED AS INPUTFORMAT
'org.apache.hadoop.hive.ql.io.avro.AvroContainerInputFormat'
OUTPUTFORMAT
'org.apache.hadoop.hive.ql.io.avro.AvroContainerOutputFormat'
TBLPROPERTIES (
'avro.schema.url'='/hive/schema/test_app_list.avsc');
But hive gives me:
FAILED: Execution Error, return code 1 from org.apache.hadoop.hive.ql.exec.DDLTask. java.lang.RuntimeException: MetaException(message:org.apache.hadoop.hive.serde2.avro.AvroSerdeException Schema for table must be of type RECORD. Received type: UNION)
hive doc shows: Supports arbitrarily nested schemas. from : https://cwiki.apache.org/confluence/display/Hive/AvroSerDe#AvroSerDe-Overview–WorkingwithAvrofromHive
data sample:
{
"appId":{"string":"com.test.app"},
"timestamp":{"long":1495893601606},
"idList":{
"array":[
{"idType":15,"id":"6c:5c:14:c3:a5:39"},
{"idType":13,"id":"eb297afe56ff340b6bb7de5c5ab09193"}
]
}
}
But I don't know how to. I need some help to fix this. Thanks!

Answer 1

the top level of the your avro schema expect to be a Record Type, that is why Hive doesn't allow this. A workaround could be create the top level as Record and inside create two fields as record Type.
{
"type": "record",
"name": "myRecord",
"namespace": "com.test.app_list"
"fields": [
{
"type": "record",
"name": "Id",
"doc": "Device ID",
"fields": [
{
"name": "idType",
"type": "int"
},{
"name": "id",
"type": "string"
}
]
},
{
"type": "record",
"name": "AppList",
"doc": "",
"fields": [
{
"name": "appId",
"type": "string",
"avro.java.string": "String"
},
{
"name": "timestamp",
"type": "long"
},
{
"name": "idList",
"type": [{"type": "array", "items": "com.test.app_list.Id"}]
}
]
}
]
}