Spark sql with JDBC


./sbin/start-master.sh

you will get master is running on a hostname and a port number. copy that and put in blow command

./bin/spark-shell --driver-memory 4G --master spark://master-host:7077 --executor-memory 8G --executor-cores 1 --num-executors 3

import java.util.Properties
val connectionProperties = new Properties()
connectionProperties.put("user", "actualUsername")
connectionProperties.put("password", "actualPassword")
val jdbcUrl = "jdbc:mysql://hostname/dbname"

val sqlquery = "(select * from t1 limit 10)tmp"

val df = spark.read.jdbc(url=jdbcUrl, table=sqlquery, properties=connectionProperties)

df.show


for ms sql: https://docs.microsoft.com/en-us/sql/connect/jdbc/building-the-connection-url?view=sql-server-2017

Comments

Post a Comment

Popular posts from this blog

Setup Nginx as a Reverse Proxy for Thingsboard running on different port/server

In this blog, we will Setup Nginx as a Reverse Proxy for Thingsboard IOT dashboard running on different port Requirement: Ubuntu Server Thingsboard installed on Ubuntu server Nginx installed on Ubuntu server For installing please refer thingsboard documentation page windows:  https://thingsboard.io/docs/user-guide/install/windows/ Linux:  https://thingsboard.io/docs/user-guide/install/linux/ Let us know in comment if you face any issue in installation we will help you. NGINX installation: sudo apt-get install nginx sudo service nginx status sudo service nginx start Open your browser and you will see the default NGinx home page, nginx also runs on default port 80 In some case if you don't see default page up then check: If using cloud machine then need to open "http port 80" on 0.0.0.0/0 or a specific ip If still don't see UI then restart server, sometime it comes after restart. Configure...
Read more

How to auto re-launch a YARN Application Master on a failure.

1)Use Case: The fundamental idea of Hadoop2 (Map-Reduce + Yarn) is to split up the two major functionalities of the JobTracker, resource management and job scheduling/monitoring, into separate daemons. The idea is to have a global ResourceManager ( RM ) and per-application ApplicationMaster ( AM ). An application is either a single job in the classical sense of Map-Reduce jobs or a DAG of jobs. The ResourceManager and per-node slave, the NodeManager ( NM ), form the data-computation framework. The ResourceManager is the ultimate authority that arbitrates resources among all the applications in the system. The per-application ApplicationMaster is, in effect, a framework specific library and is tasked with negotiating resources from the ResourceManager and working with the NodeManager(s) to execute and monitor the tasks. The ResourceManager has two main components: 1. Scheduler: is responsible for allocating resources to the various running applications. 2. Appl...
Read more

Hive partitioned tables Issue with schema & PrestoDB

It's very strange for Hive and PrestoDB user that the schema of partitioned tables in Hive is defined on partition level as well. Partition level schema and table level schema in Apache Hadoop is letting complex. Let's see the details in below example: Table schema In Hive you can change the schema of an existing table. Let’s say you have a table: CREATE TABLE TEST1 (ID INT,  NAME STRING,  RATING INT ) ROW FORMAT DELIMITED FIELDS TERMINATED BY "\t" LINES TERMINATED BY '\n' STORED AS TEXTFILE; We will focus on the third column named rating. We load few records for hdfs to this table. The file looks like this: 1         john   3.5 2   Dav   4.6 3   andy   5 hive -e "load data inpath 'input.txt' into table test1" The third column has some decimal values, but we have defined this column as integer, so the we won’t see the decimal part in the data: hive> select * from te...
Read more