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What are the best methods to load data in Hadoop?

2 Answers

1. hdfs dfs -put – simple way to insert files from local file system to HDFS.
2. HDFS Java API.
3. Sqoop – for bringing data to/from databases.
4. Flume – streaming files, logs.
5. Kafka – distributed queue, mostly for near-real time stream processing.

Which hive command will load data from HDFS file to the table?

Loading data into Hive Table

1. Using Insert Command. We can load data into a table using Insert command in two ways. One Using Values command and other is using queries.
2. Using Load. You can load data into a hive table using Load statement in two ways.
3. Using HDFS command.

How does data transfer happen from HDFS to hive?

Load Data into Hive Table from HDFS

1. Create a folder on HDFS under /user/cloudera HDFS Path.
2. Move the text file from local file system into newly created folder called javachain.
3. Create Empty table STUDENT in HIVE.
4. Load Data from HDFS path into HIVE TABLE.
5. Select the values in the Hive table.

How do I load data into hdfs?

Inserting Data into HDFS

1. You have to create an input directory. $ $HADOOP_HOME/bin/hadoop fs -mkdir /user/input.
2. Transfer and store a data file from local systems to the Hadoop file system using the put command. $ $HADOOP_HOME/bin/hadoop fs -put /home/file.txt /user/input.
3. You can verify the file using ls command.

How do I load a dataset in hdfs?

# Create directories in hdfs for the data files # command 1 hdfs dfs -mkdir /user/hive/geography # command 2 hdfs dfs -mkdir /user/hive/energy # to check that the directories have been created OK # command 3 hdfs dfs -ls /user/hive # check that your files to be loaded into hdfs are in the right place # command 4 ls -l …

How do I load data into Hive?

Loading data from flat files into Hive: hive> LOAD DATA LOCAL INPATH ‘./examples/files/kv1. txt’ OVERWRITE INTO TABLE pokes; Loads a file that contains two columns separated by ctrl-a into pokes table.

How do I load a partition table in Hive?

Hive LOAD File from HDFS into Partitioned Table

1. Create another table without partition.
2. Load data into the table (Assume state is at first column).
3. Insert into the partitioned table by selecting columns from the non-partitioned table (make sure you select state at the end).

How to load data from HDFS to hive table?

We can use the same command as above to load data from HDFS location to Hive table. We only have to remove the “LOCAL” keyword from command. There is another thing to note while loading data from HDFS location to hive table. When we load data from Local system to Hive table LOAD DATA command copies(copy+paste) file from system to HDFS.

What happens if location is not given when creating hive table?

If location is not given when you create Hive table, it uses internal Hive warehouse location and data will get moved from your source data location to internal Hive data warehouse location (i.e. /user/hive/warehouse/).

How to move data from one location to another in hive?

When you use ‘LOAD DATA INPATH’ command, the data get MOVED (instead of copy) from data location to location that you specified while creating Hive table.

Is there any alternative to ‘load data’ command in hive?

An alternative to ‘LOAD DATA’ is available in which the data will not be moved from your existing source location to hive data warehouse location. You can use ALTER TABLE command with ‘LOCATION’ option. Here is below required command