Memcached - Increment Decrement Data

Memcached incr and decr commands are used to increment or decrement the numeric value of an existing key. If the key is not found, then it returns NOT_FOUND. If the key is not numeric, then it returns CLIENT_ERROR cannot increment or decrement non-numeric value. Otherwise, ERROR is returned.

Syntax - incr

The basic syntax of Memcached incr command is as shown below −

incr key increment_value

Example

In this example, we use visitors as key and set 10 initially into it, thereafter we increment the visitors by 5.

set visitors 0 900 2
10
STORED
get visitors
VALUE visitors 0 2
10
END
incr visitors 5
15
get visitors
VALUE visitors 0 2
15
END

Syntax - decr

The basic syntax of Memcached decr command is as shown below

decr key decrement_value

Example

set visitors 0 900 2
10
STORED
get visitors
VALUE visitors 0 2
10
END
decr visitors 5
5
get visitors
VALUE visitors 0 1
5
END

Incr/Decr Using Java Apppcation

To increment or decrement data in a Memcached server, you need to use Memcached incr or decr methods respectively.

Example

import net.spy.memcached.MemcachedCpent;
pubpc class MemcachedJava {
   pubpc static void main(String[] args) {
      
      // Connecting to Memcached server on localhost
      MemcachedCpent mcc = new MemcachedCpent(new
      InetSocketAddress("127.0.0.1", 11211));
      System.out.println("Connection to server sucessfully");
      System.out.println("set status:"+mcc.set("count", 900, "5").isDone());
      
      // Get value from cache
      System.out.println("Get from Cache:"+mcc.get("count"));
      
      // now increase the stored value
      System.out.println("Increment value:"+mcc.incr("count", 2));
      
      // now decrease the stored value
      System.out.println("Decrement value:"+mcc.decr("count", 1));
      
      // now get the final stored value
      System.out.println("Get from Cache:"+mcc.get("count"));
   }
}

Output

On compipng and executing the program, you get to see the following output −

Connection to server successfully
set status:true
Get from Cache:5
Increment value:7
Decrement value:6
Get from Cache:6