How does Athena prepare a cluster of compute nodes for a specific query?

Question

Athena runs all queries in a [shared regional cluster](https://athena.guide/articles/athena-basics-running-queries).

When you submit a query, the Athena engine query planner estimates the compute capacity required to run the query and prepares a cluster of compute nodes accordingly. Some queries like DDL queries run on only one node. Complex queries over large data sets run on much bigger clusters.

How is the Athena cluster that is shared between all customers in a region different from the cluster that is prepared for a specific query?

Soumaya · Accepted Answer

- Shared Regional Cluster: This refers to the overall pool of compute resources available within a specific AWS region. All users in that region share this pool. Think of it as the total available infrastructure that Athena can draw from.  This can also be referred to as the "regional compute pool" or "regional resource pool."

- Query-Specific Cluster: When you run a query, Athena temporarily allocates a subset of nodes from the shared regional cluster to form a dedicated cluster for your query. This is tailored to the specific needs of your query, such as its complexity and data size. Once the query is completed, these resources are returned to the shared pool. You can also refer to this as the "dedicated query cluster" or "dynamic query cluster".

Adeleke Adebowale J · Answer

Amazon Athena operates in a shared regional cluster, meaning all users in the same AWS region share the same pool of resources. When you run a query, Athena temporarily allocates specific resources from this shared cluster to execute your query. The shared cluster serves all customers, while the resources for your query are isolated and used only for the duration of that query. After the query finishes, the resources are released back to the shared pool.

How does Athena prepare a cluster of compute nodes for a specific query?

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