Hive : Hive custom input/output formats .How can you use custom input/output formats in Hive?

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Introduction to Custom Input/Output Formats in Hive:

Hive allows users to define custom input and output formats to read and write data in a customized format. Custom input/output formats can be used when the default input/output formats in Hive do not meet your specific data processing needs.

In this article, we will discuss the role of custom input/output formats in Hive and how to use them.

Role of Custom Input/Output Formats in Hive:

The role of custom input/output formats in Hive is to allow users to read and write data in a customized format that is not supported by the default input/output formats. Custom input/output formats can be used to read and write data from sources such as NoSQL databases, Hadoop Distributed File System (HDFS), and cloud-based storage.

Custom input/output formats are also useful when you need to process data that is not in a structured format, such as unstructured text data, JSON data, or binary data.

How to Use Custom Input/Output Formats in Hive:

To use custom input/output formats in Hive, you need to define a custom input/output format and register it with Hive. Here are the general steps to use custom input/output formats in Hive:

  1. Define a custom input/output format: You can define a custom input/output format in Java by implementing the InputFormat or OutputFormat interface. You can also use existing libraries or frameworks such as Apache Avro, SequenceFile, or Parquet to define a custom input/output format.
  2. Register the custom input/output format with Hive: To register the custom input/output format with Hive, you can use the ADD JAR command to add the jar file containing the custom input/output format to the classpath. You can then use the CREATE TABLE command to create a table using the custom input/output format.

Here is an example of how to create a table using a custom input/output format:

ADD JAR /path/to/custom-i-o-freshers-in-format.jar;

CREATE TABLE my_table (
  col1 string,
  col2 int
)
ROW FORMAT SERDE 'com.example.CustomSerde'
WITH SERDEPROPERTIES (
  'input.format' = 'com.example.CustomInputFormat',
  'output.format' = 'com.example.CustomOutputFormat'
)
STORED AS INPUTFORMAT 'com.example.CustomInputFormat'
OUTPUTFORMAT 'com.example.CustomOutputFormat';

In the above example, we have defined a custom input/output format using the CustomInputFormat and CustomOutputFormat classes, and a custom serializer/deserializer (SerDe) using the CustomSerde class.

The ROW FORMAT clause specifies the custom SerDe to use, and the WITH SERDEPROPERTIES clause specifies the custom input/output formats to use.

The STORED AS clause specifies the input/output formats to use for the table data.

Custom input/output formats in Hive provide a way to read and write data in a customized format that is not supported by the default input/output formats. By defining custom input/output formats, you can process data from various sources and in different formats, which can be useful when working with complex data processing tasks. With the ability to define custom input/output formats, Hive provides a flexible and customizable data processing platform that can meet the needs of a wide range of users.

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