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XINFO GROUPS

Introduction​

In Dragonfly, as well as in Redis and Valkey, the XINFO GROUPS command provides information about consumer groups associated with a specific stream. This command is essential for monitoring and managing stream processing tasks, providing insights into consumer group configurations and activity.

Syntax​

XINFO GROUPS key

Parameter Explanations​

  • key: The key of the stream for which consumer groups information is requested.

Return Values​

The command returns a list of dictionaries, each dictionary representing a consumer group and its details. The details include fields such as name, consumers, pending, last-delivered-id, etc.

Code Examples​

Basic Example​

Get information about consumer groups for a stream:

dragonfly> XGROUP CREATE mystream mygroup $
OK
dragonfly> XINFO GROUPS mystream
1) 1) "name"
   2) "mygroup"
   3) "consumers"
   4) (integer) 0
   5) "pending"
   6) (integer) 0
   7) "last-delivered-id"
   8) "0-0"

Monitor Multiple Consumer Groups​

Creating and monitoring multiple consumer groups:

dragonfly> XGROUP CREATE mystream group1 $
OK
dragonfly> XGROUP CREATE mystream group2 $
OK
dragonfly> XINFO GROUPS mystream
1) 1) "name"
   2) "group1"
   3) "consumers"
   4) (integer) 0
   5) "pending"
   6) (integer) 0
   7) "last-delivered-id"
   8) "0-0"
2) 1) "name"
   2) "group2"
   3) "consumers"
   4) (integer) 0
   5) "pending"
   6) (integer) 0
   7) "last-delivered-id"
   8) "0-0"

Best Practices​

  • Regularly use XINFO GROUPS to check on the health and status of consumer groups in your stream processing architecture.
  • Ensure consumer groups are correctly created with unique and descriptive names to avoid confusion and manage them effectively.

Common Mistakes​

  • Omitting the key parameter, which is necessary to identify the stream for which group information is needed.
  • Assuming that XINFO GROUPS modifies consumer groups; it only retrieves information.

FAQs​

What happens if the stream key does not exist?​

If the stream key does not exist, XINFO GROUPS returns an empty list as there are no consumer groups associated with a nonexistent stream.

Can XINFO GROUPS be used on keys that are not streams?​

No, XINFO GROUPS is specific to streams, and attempting to use it on a non-stream key will result in an error.