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KEYS

Returns all keys matching the specified pattern.

Syntax​

KEYS pattern

Parameters​

  • pattern: The pattern to match against keys in the Redis database. The pattern can include glob-style wildcard characters:
    • * matches any sequence of characters (including an empty sequence).
    • ? matches any single character.
    • [abc] matches any one of the characters within the brackets.

Details​

  • Available since: 1.0.0
  • Time complexity: O(N), where N is the number of keys in the database. The command scans all keys and may be slow if the database contains a large number of keys.
  • ACL categories: @read

The KEYS command is used to find all keys in the Redis database that match a given pattern. It is useful for debugging or for operations where you need to retrieve a subset of keys.

Examples​

Matching All Keys​

To retrieve all keys in the database:

KEYS *

This command returns all keys in the current database.

Matching Specific Keys​

To retrieve keys that start with a certain prefix:

KEYS user:*

This command returns all keys that begin with user:.

Matching Keys with a Pattern​

To find keys with a specific pattern:

KEYS session:?????

This command matches keys that start with session: followed by exactly five characters.

RESP2/RESP3 Reply​

  • Array reply: An array of keys matching the pattern. Each key is returned as a bulk string.

Example Reply​

If the database contains the following keys: user:1, user:2, and session:12345, the reply for KEYS user:* would be:

1) "user:1"
2) "user:2"

Notes​

  • The KEYS command is not recommended for production use in large databases because it can be slow and block the server.
  • For production environments, consider using the SCAN command, which provides an incremental iteration over the keyspace and is more suitable for large datasets.
  • The KEYS command can be useful for debugging or administrative purposes where the number of keys is manageable.