Support Questions
Find answers, ask questions, and share your expertise

Spark : How to make calls to database using foreachPartition

Spark : How to make calls to database using foreachPartition

Explorer

We have spark streaming job ..writing data to AmazonDynamoDB using foreachRDD but it is very slow with our consumption rate at 10,000/sec and writing 10,000 takes 35min ...this is the code piece

From research learnt that using foreachpartition and creating a connection per partition will help ..but not sure how to go about writing code for it ..will greatly appreciate if someone can help with this ...Also any other suggestion to speed up writing is greatly appreciated

tempRequestsWithState.foreachRDD { rdd =>


    if ((rdd != null) && (rdd.count() > 0) && (!rdd.isEmpty()) ) {


      rdd.foreachPartition {


        case (topicsTableName, hashKeyTemp, attributeValueUpdate) => {
          
          val client = new AmazonDynamoDBClient()
          val request = new UpdateItemRequest(topicsTableName, hashKeyTemp, attributeValueUpdate)
          try client.updateItem(request)




        catch {


            case se: Exception => println("Error executing updateItem!\nTable ", se)


        }


        }


        case null =>




      }
    }
  }
2 REPLIES 2

Re: Spark : How to make calls to database using foreachPartition

@Aditya Mamidala

Here's a working example of foreachPartition that I've used as part of a project. This is part of a Spark Streaming process, where "event" is a DStream, and each stream is written to HBase via Phoenix (JDBC). I have a structure similar to what you tried in your code, where I first use foreachRDD then foreachPartition.

 event.map(x => x._2 ).foreachRDD { rdd =>
    rdd.foreachPartition { rddpartition =>
        val thinUrl = "jdbc:phoenix:phoenix.dev:2181:/hbase"
        val conn = DriverManager.getConnection(thinUrl)
        rddpartition.foreach { record =>
            conn.createStatement().execute("UPSERT INTO myTable VALUES (" + record._1 + ")" )
        }
        conn.commit()
    }
}

The full project is located here.

Re: Spark : How to make calls to database using foreachPartition

Explorer

Thanks for your answer @Dan Zaratsian ..i implemented a solution similar to what you suggested but still facing performance issue could you please take a look at https://community.hortonworks.com/questions/85745/spark-writing-data-to-amazondynamodb-is-slow.html