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 21, 2018 in Big Data Hadoop by Haman
• 650 points
766 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 21, 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 6, 2018 in Big Data Hadoop by Ashish
• 2,650 points
6,592 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 21, 2018 in Big Data Hadoop by Omkar
• 69,170 points
14,941 views
0 votes
1 answer

I have to ingest in hadoop cluster large number of files for testing , what is the best way to do it?

Hi@sonali, It depends on what kind of testing ...READ MORE

answered Jul 8, 2020 in Big Data Hadoop by MD
• 95,300 points
409 views
+1 vote
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
• 11,380 points
7,893 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
• 11,380 points
1,328 views
+2 votes
11 answers

hadoop fs -put command?

Hi, You can create one directory in HDFS ...READ MORE

answered Mar 16, 2018 in Big Data Hadoop by nitinrawat895
• 11,380 points
62,544 views
–1 vote
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
• 9,390 points
2,993 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, 2019 in Big Data Hadoop by Gitika
• 65,950 points
17,855 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
611 views