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Apache Hive Essentials
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Hive provides the EXPLAIN and ANALYZE statements that can be used as utilities to check and identify the performance of queries.
Hive provides an
EXPLAIN command to return a query execution plan without running the query. We can use an EXPLAIN command for queries if we have a doubt or a concern about performance. The EXPLAIN command will help to see the difference between two or more queries for the same purpose. The syntax for EXPLAIN is as follows:
EXPLAIN [EXTENDED|DEPENDENCY|AUTHORIZATION] hive_query
The following keywords can be used:
EXTENDED: This provides additional information for the operators in the plan, such as file pathname and abstract syntax tree.
DEPENDENCY: This provides a JSON format output that contains a list of tables and partitions that the query depends on. It is available since HIVE 0.10.0.
AUTHORIZATION: This lists all entities needed to be authorized including input and output to run the Hive query and authorization failures...