Skip to main content

INCR

Increments the integer value of a key by one.

Syntax​

INCR key

Parameters​

  • key: The name of the key whose value you want to increment.

Details​

  • Available since: 1.0.0
  • Time complexity: O(1)
  • ACL categories: @write, @string, @fast

The INCR command increases the integer value stored at key by one. If the key does not exist, it is set to 0 before performing the increment operation. The operation is atomic, ensuring that concurrent requests are correctly handled.

Examples​

Basic Usage​

Assume we have a key called mykey with the value "5":

SET mykey "5"

To increment the value of mykey by 1:

INCR mykey

This will return:

(integer) 6

The value of mykey will now be "6".

Handling a Non-Existent Key​

If the key does not exist:

INCR newkey

This will return:

(integer) 1

The key newkey is now set to "1".

Edge Cases​

  • If the key holds a value that is not an integer or cannot be represented as an integer, an error is returned.
  • If the resulting value after the increment operation exceeds the maximum integer value allowed (2^63 - 1), an error is returned.

RESP2/RESP3 Reply​

  • Integer reply: the value of the key after the increment operation.