Table of Contents
What happens when sqoop job fails?
Since Sqoop breaks down export process into multiple transactions, it is possible that a failed export job may result in partial data being committed to the database. This can further lead to subsequent jobs failing due to insert collisions in some cases, or lead to duplicated data in others.
What are the limitations of sqoop export?
Limitations of Sqoop
- We cannot pause or resume Apache Sqoop.
- The performance of the Sqoop Export depends on the hardware configuration of the RDBMS server.
- Sqoop uses the MapReduce paradigm in backend processing due to which it is slow.
- The failures during partial import and export need special handling.
What is sqoop used for?
Sqoop is used to transfer data from RDBMS (relational database management system) like MySQL and Oracle to HDFS (Hadoop Distributed File System). Big Data Sqoop can also be used to transform data in Hadoop MapReduce and then export it into RDBMS.
What will happen if Target Dir already exists during sqoop import *?
As the error states, the target directory you have mentioned in the sqoop command already exists in hdfs. The sqoop command creates the directory automatically. Now you can either give a new name for the directory, or delete the existing directory and then run this command again.
Which data do we query using Hive?
Using Apache Hive queries, you can query distributed data storage including Hadoop data. Hive supports ANSI SQL and atomic, consistent, isolated, and durable (ACID) transactions. For updating data, you can use the MERGE statement, which now also meets ACID standards.
Is sqoop a client program?
Client API allows you to execute the functions of sqoop commands. It requires Sqoop Client JAR and its dependencies. Client API is explained using Generic JDBC Connector properties. Before executing the application using the sqoop client API, check whether sqoop server is running.
How do I run a Sqoop script?
Executing as shell script
- vi sqoop_eval.sh and write the above sqoop eval command in the file.
- chmod +x sqoop_eval.sh (This command is giving execute permissions to the file)
- ./sqoop_eval.sh (This command is used to execute the shell-script)
Can sqoop run without Hadoop?
1 Answer. To run Sqoop commands (both sqoop1 and sqoop2 ), Hadoop is a mandatory prerequisite. You cannot run sqoop commands without the Hadoop libraries.
How does sqoop use MapReduce?
Sqoop automates most of the process, depends on the database to describe the schema of the data to be imported. Sqoop uses MapReduce framework to import and export the data, which provides parallel mechanism as well as fault tolerance. Sqoop makes developers life easy by providing command line interface.
What is Sqoop troubleshooting process?
Basically, Sqoop troubleshooting process produces more debug output on the console. Hence we can easily inspect them. Also, to see if there are any specific failures recorded we can look at the task logs from Hadoop. Since failure may occur while task execution is not relayed correctly to the console.
Why is Sqoop treating TINYINT(1) as booleans type?
Problem: It may happen that the Apache Sqoop is treating TINYINT (1) columns as the booleans types. This may cause issues with the HIVE import. This issue occurs because, by default, the MySQL JDBC connector maps TINYINT (1) to the java.sql.Types.BIT, which Apache Sqoop by default maps to Boolean.
What are the Sqoop Import Control arguments?
The other Sqoop import control arguments are: Specify the number of entries to be read from the database at once. Specify the number of mapper. Use n map tasks for importing in parallel Import the results of the statement. Specify the table column to be used to split the work units.
How to use Sqoop with Hive metastore in HDFS?
Sqoop is used mainly for uploading table data into HDFS. But if we have a Hive metastore associated with our HDFS cluster, then also we can use Apache Sqoop. Sqoop imports the data into the Hive by generating and executing the CREATE TABLE statement for defining data’s layout in the Hive.