Inserting Data into Partitions¶

Let us understand how to use insert to get data into static partitions in Spark Metastore from existing table called as orders.

Let us start spark context for this Notebook so that we can execute the code provided. You can sign up for our 10 node state of the art cluster/labs to learn Spark SQL using our unique integrated LMS.

val username = System.getProperty("user.name")

import org.apache.spark.sql.SparkSession

val username = System.getProperty("user.name")
val spark = SparkSession.
    builder.
    config("spark.ui.port", "0").
    config("spark.sql.warehouse.dir", s"/user/${username}/warehouse").
    enableHiveSupport.
    appName(s"${username} | Spark SQL - Managing Tables - DML and Partitioning").
    master("yarn").
    getOrCreate

If you are going to use CLIs, you can use Spark SQL using one of the 3 approaches.

Using Spark SQL

spark2-sql \
    --master yarn \
    --conf spark.ui.port=0 \
    --conf spark.sql.warehouse.dir=/user/${USER}/warehouse

Using Scala

spark2-shell \
    --master yarn \
    --conf spark.ui.port=0 \
    --conf spark.sql.warehouse.dir=/user/${USER}/warehouse

Using Pyspark

pyspark2 \
    --master yarn \
    --conf spark.ui.port=0 \
    --conf spark.sql.warehouse.dir=/user/${USER}/warehouse

Let us recap what is covered so far related to partitioned tables.
- We have created a table called as orders_part with order_month of type INT as partitioned column.
- We have added 4 static partitions for 201307, 201308, 201309 and 201310 using ALTER TABLE command.
- Once the table is created and partitions are added we have pre-processed the data to get data into the partitions using LOAD command.
It is not practical to use LOAD command always. We typically use INSERT via stage table to copy data into partitioned table.
We can pre-create partitions in partitioned tables and insert data into partitions using appropriate INSERT command. One need to ensure that required filter condition is applied to get the data relevant to the partition that is being populated.
We can also create partitions dynamically which we will see as part of the next topic.

%%sql

USE itversity_retail

%%sql

ALTER TABLE orders_part ADD PARTITION (order_month=201311)

%%sql

SELECT count(1) FROM orders_part

%%sql

INSERT INTO TABLE orders_part PARTITION (order_month=201311)
  SELECT * FROM orders WHERE order_date LIKE '2013-11%'

%%sql

SELECT count(1) FROM orders_part

import sys.process._

s"hdfs dfs -ls -R /user/${username}/warehouse/${username}_retail.db/orders_part" !

Apache Spark using SQL

Inserting Data into Partitions¶