Hive JSON SerDe

The Hive JSON SerDe is commonly used to process JSON data like events. These events are represented as single-line strings of JSON-encoded text separated by a new line. The Hive JSON SerDe does not allow duplicate keys in map or struct key names.

Note

The SerDe expects each JSON document to be on a single line of text with no line termination characters separating the fields in the record. If the JSON text is in pretty print format, you may receive an error message like HIVE_CURSOR_ERROR: Row is not a valid JSON Object or HIVE_CURSOR_ERROR: JsonParseException: Unexpected end-of-input: expected close marker for OBJECT when you attempt to query the table after you create it. For more information, see JSON Data Files in the OpenX SerDe documentation on GitHub.

The following example DDL statement uses the Hive JSON SerDe to create a table based on sample online advertising data. In the LOCATION clause, replace the myregion in s3://myregion.elasticmapreduce/samples/hive-ads/tables/impressions with the region identifier where you run Athena (for example, s3://us-west-2.elasticmapreduce/samples/hive-ads/tables/impressions).

CREATE EXTERNAL TABLE impressions (
    requestbegintime string,
    adid string,
    impressionid string,
    referrer string,
    useragent string,
    usercookie string,
    ip string,
    number string,
    processid string,
    browsercookie string,
    requestendtime string,
    timers struct
                <
                 modellookup:string, 
                 requesttime:string
                >,
    threadid string, 
    hostname string,
    sessionid string
)   
PARTITIONED BY (dt string)
ROW FORMAT SERDE 'org.apache.hive.hcatalog.data.JsonSerDe'
LOCATION 's3://myregion.elasticmapreduce/samples/hive-ads/tables/impressions';

Specifying timestamp formats with the Hive JSON SerDe

To parse timestamp values from string, you can add the WITH SERDEPROPERTIES subfield to the ROW FORMAT SERDE clause and use it to specify the timestamp.formats parameter. In the parameter, specify a comma-separated list of one or more timestamp patterns, as in the following example:

...
ROW FORMAT SERDE 'org.apache.hive.hcatalog.data.JsonSerDe'
WITH SERDEPROPERTIES ("timestamp.formats"="yyyy-MM-dd'T'HH:mm:ss.SSS'Z',yyyy-MM-dd'T'HH:mm:ss")
...

For more information, see Timestamps in the Apache Hive documentation.

Loading the table for querying

After you create the table, run MSCK REPAIR TABLE to load the table and make it queryable from Athena:

MSCK REPAIR TABLE impressions

Querying CloudTrail logs

You can use the Hive JSON SerDe to query CloudTrail logs. For more information and example CREATE TABLE statements, see Querying AWS CloudTrail logs.