Redis SCAN Command

Redis Key (key)

The Redis SCAN command is used to iterate over the database keys in the database.

The SCAN command is a cursor-based iterator that returns a new cursor to the user each time it is called. The user needs to use this new cursor as the cursor parameter of the SCAN command in the next iteration to continue the previous iteration process.

SCAN returns an array containing two elements, the first element is the new cursor used for the next iteration, and the second element is an array containing all the elements iterated over. If the new cursor returns 0, it means the iteration has ended.

Related Commands:

• SSCAN Command used to iterate over the elements of a set key.
• HSCAN Command used to iterate over the key-value pairs of a hash key.
• ZSCAN Command used to iterate over the elements of a sorted set (including both element members and element scores).

Syntax

Basic Syntax of redis Scan Command:

SCAN cursor [MATCH pattern] [COUNT count]

• cursor - Cursor.
• pattern - Matching pattern.
• count - Specify how many elements to return from the dataset, the default value is 10 .

Available Version

>= 2.8.0

Return Value

Array List.

Online Example

Using SCAN command to iterate:

redis 127.0.0.1:6379> scan 0   # Using 0 as the cursor, start a new iteration
1) "17"                        # The cursor returned from the first iteration
2)  1) "key:12"
    2) "key:8"
    3) "key:4"
    4) "key:14"
    5) "key:16"
    6) "key:17"
    7) "key:15"
    8) "key:10"
    9) "key:3"
   10) "key:7"
   11) "key:1"
redis 127.0.0.1:6379> scan 17  # Using the cursor returned from the first iteration 17 Start a new iteration
1) "0"
2) 1) "key:5"
   2) "key:18"
   3) "key:0"
   4) "key:2"
   5) "key:19"
   6) "key:13"
   7) "key:6"
   8) "key:9"
   9) "key:11"

Redis Key (key)