Most viewed questions in Big Data Hadoop

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How data distribution is done in Hadoop?

To understand how or what are the process ...READ MORE

Apr 4, 2019 in Big Data Hadoop by Gitika
• 65,890 points
1,875 views
0 votes
1 answer

How to reduce shuffling cost in map reduce?

You can define a Combiner function, which does the ...READ MORE

Jan 22, 2019 in Big Data Hadoop by Omkar
• 69,230 points
1,875 views
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1 answer

What is the PostgreSQL connection string for Sqoop?

The format of the connection string is: jdbc:postgresql://<HOST>:<PORT>/<DATABASE_NAME> You ...READ MORE

Jun 6, 2019 in Big Data Hadoop by Kamal
1,871 views
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1 answer

What are all the Data quality checks we do in our real time Big Data projects.

You can use a checksum to compare ...READ MORE

Sep 4, 2019 in Big Data Hadoop by Tina
1,870 views
0 votes
1 answer

Impala: Add months to current time

You can add the months using the add_months method ...READ MORE

Jun 6, 2019 in Big Data Hadoop by John
1,869 views
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1 answer

Hbase installation Issue. Cant start HRegionServer and HQuorumPeer

It seems hbase did not start properly ...READ MORE

Dec 26, 2018 in Big Data Hadoop by Omkar
• 69,230 points
1,858 views
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1 answer

ERROR org.apache.hadoop.hbase.regionserver.HRegionServer: ZooKeeper session expired

Hi@akhtar, To avoid this error you have to ...READ MORE

Mar 31, 2020 in Big Data Hadoop by MD
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1,854 views
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Setting up Hadoop Multi-node cluster on windows 10 systems

Hi@Hassan, You can do it windows system as ...READ MORE

Oct 1, 2020 in Big Data Hadoop by MD
• 95,460 points
1,839 views
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3 answers

How to specify KeyValueTextInputFormat Separator in Hadoop-.20 api?

conf.set("key.value.separator.in.input.line", ","); Job job = new ...READ MORE

Dec 5, 2018 in Big Data Hadoop by Rio
1,837 views
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1 answer

error: Access denied for user 'sample'@'localhost'.

This kind of error occurs when we ...READ MORE

Apr 15, 2019 in Big Data Hadoop by Gitika
• 65,890 points
1,835 views
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1 answer

Setting Hive/Hadoop property using Hive Query

You can set Hadoop & Hive conf ...READ MORE

Apr 18, 2018 in Big Data Hadoop by Shubham
• 13,490 points
1,832 views
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1 answer

Hadoop: ERROR datanode.DataNode: All directories in dfs.data.dir are invalid.

Hi, Try this, first delete all contents from ...READ MORE

Aug 5, 2019 in Big Data Hadoop by Gitika
• 65,890 points
1,831 views
+1 vote
1 answer

Information Unavailable:Running jps command in Hadoop

Hi, I think this is because the process ...READ MORE

Jan 21, 2020 in Big Data Hadoop by anonymous
1,822 views
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1 answer

Access DFS through Java API

It is because, may be you are ...READ MORE

Mar 23, 2018 in Big Data Hadoop by nitinrawat895
• 11,380 points
1,821 views
0 votes
1 answer

Hadoop: How to use Jps command with Sun JDK installed?

You can put JPS into your path ...READ MORE

Nov 9, 2018 in Big Data Hadoop by Omkar
• 69,230 points
1,819 views
0 votes
1 answer

Hadoop vs Data Lake

A data lake is a storage repository that holds ...READ MORE

Mar 26, 2018 in Big Data Hadoop by Ashish
• 2,650 points
1,817 views
0 votes
1 answer

How to configure Yarn from command line?

It's a bit non-intuitive, but it turns ...READ MORE

Oct 16, 2018 in Big Data Hadoop by Frankie
• 9,830 points
1,807 views
0 votes
1 answer

How do we authenticate user from http.signature.secret file?

hadoop.http.authentication.signature.secret.file: The signature secret file for signing ...READ MORE

Apr 24, 2018 in Big Data Hadoop by Shubham
• 13,490 points
1,806 views
0 votes
1 answer

How to tune Spark jobs & optimize the performance?

You need to know the cluster properly ...READ MORE

Apr 18, 2018 in Big Data Hadoop by coldcode
• 2,090 points
1,802 views
0 votes
1 answer

How to set the number of Map & Reduce tasks?

The map tasks created for a job ...READ MORE

Apr 18, 2018 in Big Data Hadoop by Shubham
• 13,490 points
1,793 views
0 votes
1 answer

How to Create a table with region replication in Hbase?

Hi, Region replication is a per-table property. All ...READ MORE

Jun 1, 2019 in Big Data Hadoop by Gitika
• 65,890 points
1,789 views
–1 vote
1 answer

Hadoop error: can not start-all.sh

Try adding <property> <name>dfs.name.dir</name> <value>/path/to/hdfs/dir</value> ...READ MORE

Jan 12, 2019 in Big Data Hadoop by Omkar
• 69,230 points
1,782 views
0 votes
1 answer

Killing oozie Jobs by userid

Suppose you want to kill the jobs ...READ MORE

Jul 29, 2019 in Big Data Hadoop by Esha
1,781 views
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1 answer

Bucketing in Hive

By default, only 1 bucket will be ...READ MORE

Feb 11, 2019 in Big Data Hadoop by Omkar
• 69,230 points
1,781 views
+1 vote
2 answers

Hadoop: Error: Exception in thread “main” java.lang.UnsupportedClassVersionError: a

The reason for this error is because ...READ MORE

Aug 6, 2019 in Big Data Hadoop by Venkita
• 240 points
1,777 views
0 votes
1 answer

Job and Task Scheduling In Hadoop

I  n case of fair scheduler, when there is ...READ MORE

Oct 31, 2018 in Big Data Hadoop by Neha
• 6,300 points
1,773 views
0 votes
1 answer

Importing a portion of Relational Database to HDFS

Yes, there is a tool called Sqoop ...READ MORE

Jul 20, 2018 in Big Data Hadoop by nitinrawat895
• 11,380 points
1,773 views
0 votes
1 answer

out of Memory Error in Hadoop

See if you can share the screenshot ...READ MORE

May 22, 2018 in Big Data Hadoop by nitinrawat895
• 11,380 points
1,772 views
0 votes
1 answer

Python read file as stream from HDFS

I could redirect to a Python library ...READ MORE

May 30, 2019 in Big Data Hadoop by ravikiran
• 4,620 points
1,771 views
0 votes
1 answer

Hadoop: No Such Method Exception

Mapper and reducer classes need to be ...READ MORE

Oct 26, 2018 in Big Data Hadoop by Omkar
• 69,230 points
1,769 views
0 votes
1 answer

Disabling Kerberos authentication in Hadoop

Make the following changes: core-site.xml(Hadoop_Dir/etc/hadoop): ...READ MORE

May 16, 2018 in Big Data Hadoop by Shubham
• 13,490 points
1,768 views
0 votes
1 answer

IDE for writing and running hadoop jobs?

You can use the Eclipse IDE. It's ...READ MORE

Apr 10, 2018 in Big Data Hadoop by kurt_cobain
• 9,390 points
1,767 views
0 votes
1 answer

Submitting MapReduce job using jobConf object vs job object

Both JobConf & Job objects are used ...READ MORE

May 4, 2018 in Big Data Hadoop by Shubham
• 13,490 points
1,765 views
0 votes
1 answer

Different ports in a Hadoop cluster environment?

Below image will help you in understanding ...READ MORE

Apr 6, 2018 in Big Data Hadoop by nitinrawat895
• 11,380 points
1,757 views
0 votes
1 answer

What do we exactly mean by “Hadoop” – the definition of Hadoop?

The official definition of Apache Hadoop given ...READ MORE

Mar 16, 2018 in Big Data Hadoop by Shubham
1,757 views
0 votes
1 answer

Why we are configuring mapred.job.tracker in YARN?

I really dont know the reason behind ...READ MORE

Mar 29, 2018 in Big Data Hadoop by Ashish
• 2,650 points
1,754 views
0 votes
1 answer

How to discover missing or corrupt HDFS data?

HDFS supports fsck command to check for ...READ MORE

Sep 19, 2018 in Big Data Hadoop by nitinrawat895
• 11,380 points
1,753 views
0 votes
1 answer

Which one is better MR or Spark?

The above difference clearly points out that ...READ MORE

Jul 15, 2019 in Big Data Hadoop by Daniel
1,751 views
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1 answer
0 votes
1 answer

Which of the following is not a hadoop output format?

The Hadoop Output Format checks the Output ...READ MORE

Dec 20, 2021 in Big Data Hadoop by Kavya
• 700 points
1,749 views
0 votes
1 answer

How to add a column in Hive table?

Hi@akhtar, You can use the alter table command ...READ MORE

Oct 19, 2020 in Big Data Hadoop by MD
• 95,460 points
1,749 views
0 votes
1 answer

Will hadoop(sqoop) load oracle faster than SQL loader?

down vote Had a similar task of exporting ...READ MORE

Sep 4, 2018 in Big Data Hadoop by Frankie
• 9,830 points
1,747 views
0 votes
1 answer

Sqoop overwrite a directory

You can use the --hive-overwrite: $ sqoop import --connect ...READ MORE

Feb 11, 2019 in Big Data Hadoop by Omkar
• 69,230 points
1,744 views
0 votes
1 answer

Secondary Sorting in Hadoop MapReduce

Grouping Comparator Once the data reaches a reducer, ...READ MORE

Sep 5, 2019 in Big Data Hadoop by ravikiran
• 4,620 points
1,741 views
0 votes
1 answer

How to import PIG data into HBase?

Follow the below steps to do it: # ...READ MORE

Feb 15, 2019 in Big Data Hadoop by Omkar
• 69,230 points
1,741 views
0 votes
1 answer

How to import selected columns in Sqoop?

If you want to import selected columns, ...READ MORE

May 15, 2019 in Big Data Hadoop by Shirish
1,734 views
0 votes
1 answer

Not able to start/stop hadoop daemons

If you were able to start the ...READ MORE

Dec 20, 2018 in Big Data Hadoop by Omkar
• 69,230 points
1,732 views
0 votes
1 answer

Error while connecting to Hive using Java JDBC

Use ​org.apache.hive.jdbc.HiveDriver as your driver ...READ MORE

Nov 22, 2018 in Big Data Hadoop by Omkar
• 69,230 points
1,729 views
0 votes
1 answer

Hadoop: What is the difference between `hadoop dfs` and `hadoop fs`?

You can find the definition here: $HADOOP_HOME/bin/hadoop ... elif [ ...READ MORE

Nov 6, 2018 in Big Data Hadoop by Omkar
• 69,230 points
1,727 views