FAQ

• General questions

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  How can I connect to the Dremio Open Catalog?

  Make sure you have configured the Open Catalog on your Dremio instance, refer to Dremio’s official Configure the Open Catalog documentation.

  The catalog endpoint URLs follow the pattern https://catalog.<DREMIO_INSTANCE_ID>.dremio.<STACKIT_REGION>.onstackit.cloud/, where DREMIO_INSTANCE_ID is the UUID of your Dremio instance, and STACKIT_REGION is the region of your STACKIT project (usually eu01). You can also find the catalog URL on the STACKIT Portal, on the “Dremio > URLs” section.

  Different authentication methods are supported, but for Machine-to-Machine applications a Dremio service user is recommended. Refer to Dremio’s official OAuth Client Credentials documentation for more details about generating OAuth client credentials for a new service user.

  You can generate a new access token by submitting an authentication request to the https://<DREMIO_INSTANCE_ID>.dremio.<STACKIT_REGION>.onstackit.cloud/oauth/token endpoint of your Dremio instance. This access token must be provided as a bearer token in your requests to the Catalog.

  I see high memory usage and hash aggregation spilling on my executor, how can I fix it?

  When executors reach their defined memory limit, Dremio spills the data to disk. This usually happens when:

  • Executing memory-intensive hash aggregation queries (GROUP BY queries) that process large datasets.
  • Working with memory limited environments.

  You can prevent performance degradation by either optimizing the query leading to high memory consumption, or by changing the engine configuration to give the executors more memory.

  For more details on how to edit engine settings, refer to Dremio’s official Editing the Engine Settings documentation.