Spark - Save DataFrame to Hive Table

From Spark 2.0, you can easily read data from Hive data warehouse and also write/append new data to Hive tables.

This page shows how to operate with Hive in Spark including:

Create DataFrame from existing Hive table
Save DataFrame to a new Hive table
Append data to the existing Hive table via both INSERT statement and append write mode.

Python is used as programming language. The syntax for Scala will be very similar.

Create a SparkSession with Hive supported

Run the following code to create a Spark session with Hive support:

from pyspark.sql import SparkSessionappName = "PySpark Hive Example"master = "local"# Create Spark session with Hive supported.spark = SparkSession.builder \.appName(appName) \.master(master) \.enableHiveSupport() \.getOrCreate()

Read data from Hive

And now we can use the SparkSession object to read data from Hive database:

# Read data from Hive database test_db, table name: test_table.df = spark.sql("select * from test_db.test_table")df.show()

I use Derby as Hive metastore and I already created on database named test_db with a table named test_table. Inside the table, there are two records.

The results look similar to the following:

+---+-----+
| id|value|
+---+-----+
|  1|  ABC|
|  2|  DEF|
+---+-----+

Add a new column

# Let's add a new columndf = df.withColumn("NewColumn",lit('Test'))df.show()

The following is the result:

+---+-----+---------+
| id|value|NewColumn|
+---+-----+---------+
|  1|  ABC|     Test|
|  2|  DEF|     Test|
+---+-----+---------+

Save DataFrame as a new Hive table

Use the following code to save the data frame to a new hive table named test_table2:

# Save df to a new table in Hivedf.write.mode("overwrite").saveAsTable("test_db.test_table2")# Show the results using SELECTspark.sql("select * from test_db.test_table2").show()

In the logs, I can see the new table is saved as Parquet by default:

Initialized Parquet WriteSupport with Catalyst schema: { "type" : "struct", "fields" : [ { "name" : "id", "type" : "long", "nullable" : true, "metadata" : { } }, { "name" : "value", "type" : "string", "nullable" : true, "metadata" : { "HIVE_TYPE_STRING" : "varchar(100)" } }, { "name" : "NewColumn", "type" : "string", "nullable" : false, "metadata" : { } } ] } and corresponding Parquet message type: message spark_schema { optional int64 id; optional binary value (UTF8); required binary NewColumn (UTF8); }

Append data to existing Hive table

You can also append data to existing Hive table either via ‘INSERT SQL statement’ or ‘append’ write mode.

# Append data via SQLspark.sql("insert into test_db.test_table2 values (3, 'GHI', 'SQL INSERT')")spark.sql("select * from test_db.test_table2").show()# Append data via codedf = spark.sql("select 4 as id, 'JKL' as value, 'Spark Write Append Mode' as NewColumn")df.show()df.write.mode("append").saveAsTable("test_db.test_table2")spark.sql("select * from test_db.test_table2").show()

Both records are inserted into the table successfully as the following output shows:

+---+-----+--------------------+
| id|value|           NewColumn|
+---+-----+--------------------+
|  4|  JKL|Spark Write Appen...|
|  1|  ABC|                Test|
|  2|  DEF|                Test|
|  3|  GHI|          SQL INSERT|
+---+-----+--------------------+

Complete code - hive-example.py

from pyspark.sql import SparkSession
from pyspark.sql.functions import lit

appName = "PySpark Hive Example"
master = "local"

# Create Spark session with Hive supported.
spark = SparkSession.builder \
    .appName(appName) \
    .master(master) \
    .enableHiveSupport() \
    .getOrCreate()

# Read data from Hive database test_db, table name: test_table.
df = spark.sql("select * from test_db.test_table")
df.show()

# Let's add a new column
df = df.withColumn("NewColumn",lit('Test'))
df.show()

# Save df to a new table in Hive
df.write.mode("overwrite").saveAsTable("test_db.test_table2")
# Show the results using SELECT
spark.sql("select * from test_db.test_table2").show()

# Append data via SQL
spark.sql("insert into test_db.test_table2 values (3, 'GHI', 'SQL INSERT')")
spark.sql("select * from test_db.test_table2").show()

# Append data via code
df = spark.sql("select 4 as id, 'JKL' as value, 'Spark Write Append Mode' as NewColumn")
df.show()
df.write.mode("append").saveAsTable("test_db.test_table2")
spark.sql("select * from test_db.test_table2").show()

Have fun with Spark!