Problem Scenario 50 : You have been given below code snippet (calculating an average score}, with intermediate output.
type ScoreCollector = (Int, Double)
type PersonScores = (String, (Int, Double))
val initialScores = Array(("Fred", 88.0), ("Fred", 95.0), ("Fred", 91.0), ("Wilma", 93.0), ("Wilma", 95.0), ("Wilma", 98.0))
val wilmaAndFredScores = sc.parallelize(initialScores).cache()
val scores = wilmaAndFredScores.combineByKey(createScoreCombiner, scoreCombiner, scoreMerger)
val averagingFunction = (personScore: PersonScores) => { val (name, (numberScores, totalScore)) = personScore (name, totalScore / numberScores)
}
val averageScores = scores.collectAsMap(}.map(averagingFunction)
Expected output: averageScores: scala.collection.Map[String,Double] = Map(Fred -> 91.33333333333333, Wilma -> 95.33333333333333)
Define all three required function , which are input for combineByKey method, e.g. (createScoreCombiner, scoreCombiner, scoreMerger). And help us producing required results.
Problem Scenario 34 : You have given a file named spark6/user.csv.
Data is given below:
user.csv
id,topic,hits
Rahul,scala,120
Nikita,spark,80
Mithun,spark,1
myself,cca175,180
Now write a Spark code in scala which will remove the header part and create RDD of values as below, for all rows. And also if id is myself" than filter out row.
Map(id -> om, topic -> scala, hits -> 120)
Problem Scenario 15 : You have been given following mysql database details as well as other info.
user=retail_dba
password=cloudera
database=retail_db
jdbc URL = jdbc:mysql://quickstart:3306/retail_db
Please accomplish following activities.
1. In mysql departments table please insert following record. Insert into departments values(9999, '"Data Science"1);
2. Now there is a downstream system which will process dumps of this file. However, system is designed the way that it can process only files if fields are enlcosed in(') single quote and separate of the field should be (-} and line needs to be terminated by : (colon).
3. If data itself contains the " (double quote } than it should be escaped by \.
4. Please import the departments table in a directory called departments_enclosedby and file should be able to process by downstream system.
Problem Scenario 48 : You have been given below Python code snippet, with intermediate output.
We want to take a list of records about people and then we want to sum up their ages and count them.
So for this example the type in the RDD will be a Dictionary in the format of {name: NAME, age:AGE, gender:GENDER}.
The result type will be a tuple that looks like so (Sum of Ages, Count)
people = []
people.append({'name':'Amit', 'age':45,'gender':'M'})
people.append({'name':'Ganga', 'age':43,'gender':'F'})
people.append({'name':'John', 'age':28,'gender':'M'})
people.append({'name':'Lolita', 'age':33,'gender':'F'})
people.append({'name':'Dont Know', 'age':18,'gender':'T'})
peopleRdd=sc.parallelize(people) //Create an RDD
peopleRdd.aggregate((0,0), seqOp, combOp) //Output of above line : 167, 5)
Now define two operation seqOp and combOp , such that
seqOp : Sum the age of all people as well count them, in each partition. combOp : Combine results from all partitions.
Problem Scenario 78 : You have been given MySQL DB with following details.
user=retail_dba
password=cloudera
database=retail_db
table=retail_db.orders
table=retail_db.order_items
jdbc URL = jdbc:mysql://quickstart:3306/retail_db
Columns of order table : (orderid , order_date , order_customer_id, order_status)
Columns of ordeMtems table : (order_item_td , order_item_order_id , order_item_product_id, order_item_quantity,order_item_subtotal,order_item_product_price)
Please accomplish following activities.
1. Copy "retail_db.orders" and "retail_db.order_items" table to hdfs in respective directory p92_orders and p92_order_items .
2. Join these data using order_id in Spark and Python
3. Calculate total revenue perday and per customer
4. Calculate maximum revenue customer
Problem Scenario 21 : You have been given log generating service as below.
startjogs (It will generate continuous logs)
tailjogs (You can check , what logs are being generated)
stopjogs (It will stop the log service)
Path where logs are generated using above service : /opt/gen_logs/logs/access.log
Now write a flume configuration file named flumel.conf , using that configuration file dumps logs in HDFS file system in a directory called flumel. Flume channel should have following property as well. After every 100 message it should be committed, use non-durable/faster channel and it should be able to hold maximum 1000 events
Solution :
Step 1 : Create flume configuration file, with below configuration for source, sink and channel.
#Define source , sink , channel and agent,
agent1 .sources = source1
agent1 .sinks = sink1
agent1.channels = channel1
# Describe/configure source1
agent1 .sources.source1.type = exec
agent1.sources.source1.command = tail -F /opt/gen logs/logs/access.log
## Describe sinkl
agentl .sinks.sinkl.channel = memory-channel
agentl .sinks.sinkl .type = hdfs
agentl .sinks.sink1.hdfs.path = flumel
agentl .sinks.sinkl.hdfs.fileType = Data Stream
# Now we need to define channell property.
agent1.channels.channel1.type = memory
agent1.channels.channell.capacity = 1000
agent1.channels.channell.transactionCapacity = 100
# Bind the source and sink to the channel
agent1.sources.source1.channels = channel1
agent1.sinks.sink1.channel = channel1
Step 2 : Run below command which will use this configuration file and append data in hdfs.
Start log service using : startjogs
Start flume service:
flume-ng agent -conf /home/cloudera/flumeconf -conf-file /home/cloudera/flumeconf/flumel.conf-Dflume.root.logger=DEBUG,INFO,console
Wait for few mins and than stop log service.
Stop_logs
Problem Scenario 20 : You have been given MySQL DB with following details.
user=retail_dba
password=cloudera
database=retail_db
table=retail_db.categories
jdbc URL = jdbc:mysql://quickstart:3306/retail_db
Please accomplish following activities.
1. Write a Sqoop Job which will import "retaildb.categories" table to hdfs, in a directory name "categories_targetJob".
Problem Scenario 33 : You have given a files as below.
spark5/EmployeeName.csv (id,name)
spark5/EmployeeSalary.csv (id,salary)
Data is given below:
EmployeeName.csv
E01,Lokesh
E02,Bhupesh
E03,Amit
E04,Ratan
E05,Dinesh
E06,Pavan
E07,Tejas
E08,Sheela
E09,Kumar
E10,Venkat
EmployeeSalary.csv
E01,50000
E02,50000
E03,45000
E04,45000
E05,50000
E06,45000
E07,50000
E08,10000
E09,10000
E10,10000
Now write a Spark code in scala which will load these two tiles from hdfs and join the same, and produce the (name.salary) values.
And save the data in multiple tile group by salary (Means each file will have name of employees with same salary). Make sure file name include salary as well.
Problem Scenario 60 : You have been given below code snippet.
val a = sc.parallelize(List("dog", "salmon", "salmon", "rat", "elephant"}, 3}
val b = a.keyBy(_.length)
val c = sc.parallelize(List("dog","cat","gnu","salmon","rabbit","turkey","woif","bear","bee"), 3)
val d = c.keyBy(_.length)
operation1
Write a correct code snippet for operationl which will produce desired output, shown below.
Array[(lnt, (String, String))] = Array((6,(salmon,salmon)), (6,(salmon,rabbit)), (6,(salmon,turkey)), (6,(salmon,salmon)), (6,(salmon,rabbit)),
(6,(salmon,turkey)), (3,(dog,dog)), (3,(dog,cat)), (3,(dog,gnu)), (3,(dog,bee)), (3,(rat,dog)), (3,(rat,cat)), (3,(rat,gnu)), (3,(rat,bee)))
Problem Scenario 68 : You have given a file as below.
spark75/f ile1.txt
File contain some text. As given Below
spark75/file1.txt
Apache Hadoop is an open-source software framework written in Java for distributed storage and distributed processing of very large data sets on computer clusters built from commodity hardware. All the modules in Hadoop are designed with a fundamental assumption that hardware failures are common and should be automatically handled by the framework
The core of Apache Hadoop consists of a storage part known as Hadoop Distributed File System (HDFS) and a processing part called MapReduce. Hadoop splits files into large blocks and distributes them across nodes in a cluster. To process data, Hadoop transfers packaged code for nodes to process in parallel based on the data that needs to be processed.
his approach takes advantage of data locality nodes manipulating the data they have access to to allow the dataset to be processed faster and more efficiently than it would be in a more conventional supercomputer architecture that relies on a parallel file system where computation and data are distributed via high-speed networking
For a slightly more complicated task, lets look into splitting up sentences from our documents into word bigrams. A bigram is pair of successive tokens in some sequence. We will look at building bigrams from the sequences of words in each sentence, and then try to find the most frequently occuring ones.
The first problem is that values in each partition of our initial RDD describe lines from the file rather than sentences. Sentences may be split over multiple lines. The glom() RDD method is used to create a single entry for each document containing the list of all lines, we can then join the lines up, then resplit them into sentences using "." as the separator, using flatMap so that every object in our RDD is now a sentence.
A bigram is pair of successive tokens in some sequence. Please build bigrams from the sequences of words in each sentence, and then try to find the most frequently occuring ones.
TESTED 05 Feb 2025
