what is difference between "ORDER BY" and "SORT BY in hive

8/5/2023

Diagram illustrating how ORDER BY performs global sorting across all reducers in Hive.

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what is difference  between "ORDER BY" and "SORT BY in hive 

When working with Apache Hive, understanding the difference between ORDER BY and SORT BY is crucial for optimizing query performance, especially when dealing with large datasets. Both clauses are used for sorting data, but they behave differently and are suited for different scenarios. Let’s dive into the details.
 

What is ORDER BY in Hive?

The ORDER BY clause in Hive is used to perform a global sort of the entire dataset. Here’s how it works:

  • All data is collected into a single reducer.
  • The reducer sorts the data globally.
  • The sorted result is returned.
"ORDER BY" can be resource-intensive and may not be suitable for large in hive.
 
Example 
 
SELECT name, age
FROM users
ORDER BY age;
 

What is SORT BY in Hive?

The SORT BY clause, on the other hand, sorts data within each reducer independently. Here’s how it works:

  • Data is distributed across multiple reducers.
  • Each reducer sorts its portion of the data.
  • The result is not globally sorted but sorted within each reducer.
"SORT BY" is used for sorting the data within each reducer task. 
It does not perform a global sort across all data but sorts the data within each reducer independently.
 
"SORT BY" be suitable for large in hive.
 
Example 
 
SELECT name, age
FROM users
ORDER BY age;
# Diagram illustrating how ORDER BY performs global sorting across all reducers in Hive.

Conclusion

In Hive, ORDER BY and SORT BY serve different purposes and are optimized for different scenarios. ORDER BY is ideal for global sorting but can be resource-intensive for large datasets. On the other hand, SORT BY is more efficient for large datasets as it sorts data within individual reducers. By understanding these differences, you can choose the right sorting method for your Hive queries and improve.

 

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