What is the meaning of Write Ahead Log in Hadoop?

0 votes
Can someone explain to me in brief about Write Ahead Log (WAL)?
Nov 20, 2018 in Big Data Hadoop by Haman
• 640 points
75 views

1 answer to this question.

0 votes

Write Ahead Log (WAL) is a file attached to every Region Server inside the distributed environment. The WAL stores the new data that hasn’t been persisted or committed to the permanent storage. It is used in case of failure to recover the data sets.

answered Nov 20, 2018 by Sunil

Related Questions In Big Data Hadoop

0 votes
1 answer

What is the use of sequence file in Hadoop?

Sequence files are binary files containing serialized ...READ MORE

answered Apr 5, 2018 in Big Data Hadoop by Ashish
• 2,630 points
650 views
0 votes
1 answer
0 votes
1 answer

What is the use of fsimage in hadoop?

The NameNode stores modifications to the file ...READ MORE

answered Dec 20, 2018 in Big Data Hadoop by Omkar
• 67,120 points
607 views
0 votes
1 answer
0 votes
1 answer

Hadoop Mapreduce word count Program

Firstly you need to understand the concept ...READ MORE

answered Mar 16, 2018 in Data Analytics by nitinrawat895
• 10,070 points
2,040 views
0 votes
1 answer

hadoop.mapred vs hadoop.mapreduce?

org.apache.hadoop.mapred is the Old API  org.apache.hadoop.mapreduce is the ...READ MORE

answered Mar 16, 2018 in Data Analytics by nitinrawat895
• 10,070 points
193 views
0 votes
10 answers

hadoop fs -put command?

copy command can be used to copy files ...READ MORE

answered Dec 7, 2018 in Big Data Hadoop by Sujay
10,408 views
0 votes
1 answer

Hadoop dfs -ls command?

In your case there is no difference ...READ MORE

answered Mar 16, 2018 in Big Data Hadoop by kurt_cobain
• 9,240 points
762 views
0 votes
12 answers

What is Zookeeper? What is the purpose of Zookeeper in Hadoop Ecosystem?

Hey, Apache Zookeeper says that it is a ...READ MORE

answered Apr 29 in Big Data Hadoop by Gitika
• 19,720 points
3,184 views
0 votes
1 answer

What is the usage of Configured class in Hadoop programs?

Configured is a default implementation of the Configurable interface - ...READ MORE

answered Nov 22, 2018 in Big Data Hadoop by Frankie
• 9,810 points
98 views