Hive-BigQuery StorageHandler [No Longer Maintained]

This is a Hive StorageHandler plugin that enables Hive to interact with BigQuery. It allows you keep your existing pipelines but move to BigQuery. It utilizes the high throughput BigQuery Storage API to read data and uses the BigQuery API to write data.

The following steps are performed under Dataproc cluster in Google Cloud Platform. If you need to run in your cluster, you will need setup Google Cloud SDK and Google Cloud Storage connector for Hadoop.

Getting the StorageHandler

1. Check it out from GitHub.
2. Build it with the new Google Hadoop BigQuery Connector

git clone https://github.com/GoogleCloudPlatform/hive-bigquery-storage-handler  
cd hive-bigquery-storage-handler  
mvn clean install  

3. Deploy hive-bigquery-storage-handler-1.0-shaded.jar

Using the StorageHandler to access BigQuery

1. Enable the BigQuery Storage API. Follow these instructions and check pricing details

2. Copy the compiled Jar to a Google Cloud Storage bucket that can be accessed by your hive cluster

3. Open Hive CLI and load the jar as shown below:

hive> add jar gs://<Jar location>/hive-bigquery-storage-handler-1.0-shaded.jar;  

4. Verify the jar is loaded successfully

hive> list jars;  

At this point you can operate Hive just like you used to do.

Creating BigQuery tables

If you have BigQuery table already, here is how you can define Hive table that refer to it:

CREATE TABLE bq_test (word_count bigint, word string)  
 STORED BY 
 'com.google.cloud.hadoop.io.bigquery.hive.HiveBigQueryStorageHandler' 
 TBLPROPERTIES ( 
 'bq.dataset'='<BigQuery dataset name>', 
 'bq.table'='<BigQuery table name>', 
 'mapred.bq.project.id'='<Your Project ID>', 
 'mapred.bq.temp.gcs.path'='gs://<Bucket name>/<Temporary path>', 
 'mapred.bq.gcs.bucket'='<Cloud Storage Bucket name>' 
 );

You will need to provide the following table properties:

Data Type Mapping

Filtering

The new API allows column pruning and predicate filtering to only read the data you are interested in.

Column Pruning

Since BigQuery is backed by a columnar datastore, it can efficiently stream data without reading all columns.

Predicate Filtering

The Storage API supports arbitrary pushdown of predicate filters. To enable predicate pushdown ensure hive.optimize.ppd is set to true.
Filters on all primitive type columns will be pushed to storage layer improving the performance of reads. Predicate pushdown is not supported on complex types such as arrays and structs. For example - filters like address.city = "Sunnyvale" will not get pushdown to Bigquery.

Caveats

1. Ensure that table exists in bigquery and column names are always lowercase
2. timestamp column in hive is interpreted to be timezoneless and stored as an offset from the UNIX epoch with milliseconds precision.
   To display in human readable format from_unix_time udf can be used as

   from_unixtime(cast(cast(<timestampcolumn> as bigint)/1000 as bigint), 'yyyy-MM-dd hh:mm:ss')      
   

Issues

1. Writing to BigQuery will fail when using Apache Tez as the execution engine. As a workaround set hive.execution.engine=mr to use MapReduce as the execution engine
2. STRUCT type is not supported unless avro schema is explicitly specified using either avro.schema.literal or avro.schema.url table properties. Below table contains all supported types defining schema explicitly. Note: If table doesn't need struct then specifying schema is optional

    CREATE TABLE dbname.alltypeswithSchema(currenttimestamp TIMESTAMP,currentdate DATE, userid BIGINT, sessionid STRING, skills Array<String>,
      eventduration DOUBLE, eventcount BIGINT, is_latest BOOLEAN,keyset BINARY,addresses ARRAY<STRUCT<status: STRING, street: STRING,city: STRING, state: STRING,zip: BIGINT>> )
      STORED BY 'com.google.cloud.hadoop.io.bigquery.hive.HiveBigQueryStorageHandler'
      TBLPROPERTIES (
       'bq.dataset'='bqdataset',
       'bq.table'='bqtable',
       'mapred.bq.project.id'='bqproject',
       'mapred.bq.temp.gcs.path'='gs://bucketname/prefix',
       'mapred.bq.gcs.bucket'='bucketname',
       'avro.schema.literal'='{"type":"record","name":"alltypesnonnull",
           "fields":[{"name":"currenttimestamp","type":["null",{"type":"long","logicalType":"timestamp-micros"}], "default" : null}
                    ,{"name":"currentdate","type":{"type":"int","logicalType":"date"}, "default" : -1},{"name":"userid","type":"long","doc":"User identifier.", "default" : -1}
                    ,{"name":"sessionid","type":["null","string"], "default" : null},{"name":"skills","type":["null", {"type":"array","items":"string"}], "default" : null}
                    ,{"name":"eventduration","type":["null","double"], "default" : null},{"name":"eventcount","type":["null","long"], "default" : null}
                    ,{"name":"is_latest","type":["null","boolean"], "default" : null},{"name":"keyset","type":["null","bytes"], "default" : null}
                    ,{"name":"addresses","type":["null", {"type":"array",
                       "items":{"type":"record","name":"__s_0",
                       "fields":[{"name":"status","type":"string"},{"name":"street","type":"string"},{"name":"city","type":"string"},{"name":"state","type":"string"},{"name":"zip","type":"long"}]
                       }}], "default" : null
                     }
                   ]
           }'
      );