Memcached – Delete Key

Memcached delete command is used to delete an existing key from the Memcached server. It means it removes an item from the cache if it exists.

Syntax

Here,

key: It is the key data stored and retrieved from Memcached.

noreply: It is an optional parameter. It is used to inform the server not to send any reply.

Return Value

This command will return the following value:

DELETED: Means successful deletion.

ERROR: It shows error while deleting data or when the syntax is wrong.

NOT_FOUND: shows that the key does not exist in the Memcached server.

Example in Ubuntu

Let’s see an example for the delete command. Here we will use ‘city’ as the key and store ‘bangalore’ in it with the expiration of time 900 seconds. After this, delete command is used to delete the key ‘city.’

  set city 0 900 9  bangalore  STORED  get city  VALUE city 0 9  bangalore  END  delete city  DELETED  get city  END  delete city  NOT_FOUND  

Example in Windows:

  set city 0 900 9  bangalore  STORED  get city  VALUE city 0 9  bangalore  END  delete city  DELETED  get city  END  delete city  NOT_FOUND  

Memcached Server:

Memcached Client:

Delete data using Java Application

Let’s consider Memcached server is running on host 127.0.0.1 and port 11211. Here, we will use delete() method to delete the data from a Memcached server.

Example 1

  import net.spy.memcached.MemcachedClient;  public class MemcachedJava {     public static void main(String[] args) {                // Connecting to Memcached server on localhost        MemcachedClient mcc = new MemcachedClient(new        InetSocketAddress(“127.0.0.1”, 11211));        System.out.println(“Connection to server successful”);        System.out.println(“set status:”+mcc.set(“city”, 900, “bangalore”).done);                // Get value from cache        System.out.println(“Get from Cache:”+mcc.get(“city”));                // delete value from cache        System.out.println(“Delete from Cache:”+mcc.delete(“city”).isDone());                // check whether value exists or not        System.out.println(“Get from Cache:”+mcc.get(“city”));     }  }  

Output:

Connection to server successful  set status: true  Get from Cache: Bangalore  Delete from Cache: true  Get from Cache: null

Example 2

  import java.net.InetSocketAddress;  import java.util.concurrent.Future;    import net.spy.memcached.MemcachedClient;    public class MemcachedJava {     public static void main(String[] args) {             try{                // Connecting to Memcached server on localhost           MemcachedClient mcc = new MemcachedClient(new InetSocketAddress(“127.0.0.1”, 11211));           System.out.println(“Connection to server sucessful.”);             // add data to memcached server           Future fo = mcc.set(“tutoraspire”, 900, “largest online tutorials library”);             // print status of set method           System.out.println(“set status:” + fo.get());             // retrieve and check the value from cache           System.out.println(“tutoraspire value in cache – ” + mcc.get(“tutoraspire”));             // try to delete data with existing key           Future fo = mcc.delete(“tutoraspire”);             // print status of delete method           System.out.println(“delete status:” + fo.get());             // retrieve and check the value from cache           System.out.println(“tutoraspire value in cache – ” + mcc.get(“codingground”));             // Shutdowns the memcached client           mcc.shutdown();                   }catch(Exception ex)           System.out.println(ex.getMessage());     }  }  

Output:

Connection to server successful  set status:true  tutoraspire value in cache - largest online tutorials library  delete status:true  tutoraspire value in cache - null

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Memcached Delete Key