Syntax

set key flags exptime bytes [noreply] 
value 

• key - It is the name of the unique key by which data is accessed.
• flags - It is the 32-bit unsigned integer that the server stores with the data provided by the user, and returns along with the data when the item is retrieved.
• exptime - It is the expiration time (seconds) of data stored in cache. A 0 value means "never expire", i.e. it should not be removed from the cache unless required. If the exptime is more than 30 days then Memcached interprets it as UNIX timestamp for expiration.
• bytes - This is the length of the data in bytes that needs to be stored in Memcached.
• noreply (optional) - This parameter informs the server not to send any reply.
• value - It is the data that needs to be stored. The data needs to be given on the new line after executing the command with the above options.

Example

key → tutorialspoint
flag → 0
exptime → 900 (expiry time in seconds)
bytes → 9 (size of data balue in bytes)
value → memcached

set tutorialspoint 0 900 9
memcached
STORED

get tutorialspoint
VALUE tutorialspoint 0 9
memcached

END

Output

STORED

• STORED indicates success.
• ERROR indicates incorrect syntax or error while saving data.

Set Data Using Java Application

Example

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.");
      
         // now set data into memcached server
         Future fo = mcc.set("tutorialspoint", 900, "Free Education");
      
         // print status of set method
         System.out.println("set status:" + fo.get());
         
         // retrieve and check the value from cache
         System.out.println("tutorialspoint value in cache - " + mcc.get("tutorialspoint"));

         // Shutdowns the memcached client
         mcc.shutdown();
         
      }catch(Exception ex){
         System.out.println( ex.getMessage() );
      }
   }
}

Output

Connection to server successful.
set status:true
tutorialspoint value in cache - Free Education

Syntax

add key flags exptime bytes [noreply]
value

• key - It is the name of the unique key by which data is accessed.
• flags - It is the 32-bit unsigned integer that the server stores with the data provided by the user, and returns along with the data when the item is retrieved.
• exptime - It is the expiration time (seconds) of data stored in cache. A 0 value means "never expire", i.e. it should not be removed from the cache unless required. If the exptime is more than 30 days then Memcached interprets it as UNIX timestamp for expiration.
• bytes - This is the length of the data in bytes that needs to be stored in Memcached.
• noreply (optional) - This parameter informs the server not to send any reply.
• value - It is the data that needs to be stored. The data needs to be given on the new line after executing the command with the above options.

Example

key → new_key
flag → 0
exptime → 900 (expiry time in seconds)
bytes → 10 (size of data balue in bytes)
value → data_value

add new_key 0 900 10
data_value
STORED
get new_key
VALUE new_key 0 10
data_value
END

Output

STORED

• STORED indicates success.
• NOT_STORED indicates the data is not stored in Memcached.

Failure Output

add new_key 0 900 5
redis
NOT_STORED

Add Data Using Java Application

Example

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("tutorialspoint", 900, "Free Education");

         // print status of set method
         System.out.println("set status:" + fo.get());

         // retrieve and check the value from cache
         System.out.println("tutorialspoint value in cache - " + mcc.get("tutorialspoint"));

         // try to add data with existing key
         Future fo = mcc.add("tutorialspoint", 900, "memcached");

         // print status of set method
         System.out.println("add status:" + fo.get());

         // adding a new key to memcached server
         fo = mcc.add("codingground", 900, "All Free Compilers");

         // print status of set method
         System.out.println("add status:" + fo.get());
         
         // retrieve and check the value from cache
         System.out.println("codingground 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
tutorialspoint value in cache - Free Education
add status:false
add status:true
codingground value in cache - All Free Compilers

Memcached - Replace Data

Syntax

replace key flags exptime bytes [noreply]
value

• key - It is the name of the unique key by which data is accessed.
• flags - It is the 32-bit unsigned integer that the server stores with the data provided by the user, and returns along with the data when the item is retrieved.
• exptime - It is the expiration time (seconds) of data stored in cache. A 0 value means "never expire", i.e. it should not be removed from the cache unless required. If the exptime is more than 30 days then Memcached interprets it as UNIX timestamp for expiration.
• bytes - This is the length of the data in bytes that needs to be stored in Memcached.
• noreply (optional) - This parameter informs the server not to send any reply.
• value - It is the data that needs to be stored. The data needs to be given on the new line after executing the command with the above options.

Example

key → mykey
flag → 0
exptime → 900
bytes → 10 (expiry time in seconds)
value → data_value (size of data balue in bytes)

add mykey 0 900 10
data_value
STORED
get mykey
VALUE mykey 0 10
data_value
END
replace mykey 0 900 16
some_other_value
get key
VALUE mykey 0 16
some_other_value
END

Output

STORED

• STORED indicates success.
• NOT_STORED indicates the data is not stored in Memcached.

Replace Data Using Java Application

Example

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.");

         // First add a key and value
         Future fo = mcc.set("tutorialspoint", 900, "Free Education");

         // print status of add method
         System.out.println("add status:" + fo.get());

         // retrieve and check the value from cache
         System.out.println("tutorialspoint value in cache - " + mcc.get("tutorialspoint"));

         // adding a new key to memcached server
         fo = mcc.replace("tutorialspoint", 900, "Largest Tutorials' Library");

         // print status of set method
         System.out.println("replace status:" + fo.get());

         // retrieve and check the value from cache
         System.out.println("tutorialspoint value in cache - " + mcc.get("tutorialspoint"));

         // Shutdowns the memcached client
         mcc.shutdown();
         
      }catch(Exception ex){
         System.out.println( ex.getMessage() );
      }
   }
}

Output

Connection to server successful.
set status:true
tutorialspoint value in cache - Free Education
Replace status:true
tutorialspoint value in cache - Largest Tutorials' Library

Memcached - Append Data

Syntax

append key flags exptime bytes [noreply]
value

• key - It is the name of the unique key by which data is accessed.
• flags - It is the 32-bit unsigned integer that the server stores with the data provided by the user, and returns along with the data when the item is retrieved.
• exptime - It is the expiration time (seconds) of data stored in cache. A 0 value means "never expire", i.e. it should not be removed from the cache unless required. If the exptime is more than 30 days then Memcached interprets it as UNIX timestamp for expiration.
• bytes - This is the length of the data in bytes that needs to be stored in Memcached.
• noreply (optional) - This parameter informs the server not to send any reply.
• value - It is the data that needs to be stored. The data needs to be given on the new line after executing the command with the above options.

Example

• First we store a key (tutorials) and value (memcached) to Memcached
• Then, We retrieve the value using get command and check it
• Then, we append "redis" to the key tutorials
• and, we retrieve it and check again.

set tutorials 0 900 9
memcached
STORED
get tutorials
VALUE tutorials 0 14
memcached
END
append tutorials 0 900 5
redis
STORED
get tutorials
VALUE tutorials 0 14
memcachedredis
END

Output

STORED

• STORED indicates success.
• NOT_STORED indicates the key does not exist in the Memcached server.
• CLIENT_ERROR indicates error.

Append Data Using Java Application

Example

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("tutorialspoint", 900, "Free Education");

         // print status of set method
         System.out.println("set status:" + fo.get());

         // retrieve and check the value from cache
         System.out.println("tutorialspoint value in cache - " + mcc.get("tutorialspoint"));

         // try to add data with existing key
         Future fo = mcc.append("tutorialspoint", 900, " for All");

         // print status of set method
         System.out.println("append status:" + fo.get());
         
         // retrieve and check the value from cache
         System.out.println("tutorialspoint 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
tutorialspoint value in cache - Free Education
append status:true
tutorialspoint value in cache - Free Education for All

Memcached - Prepend Data

Syntax

prepend key flags exptime bytes [noreply]
value

• key - It is the name of the unique key by which data is accessed.
• flags - It is the 32-bit unsigned integer that the server stores with the data provided by the user, and returns along with the data when the item is retrieved.
• exptime - It is the expiration time (seconds) of data stored in cache. A 0 value means "never expire", i.e. it should not be removed from the cache unless required. If the exptime is more than 30 days then Memcached interprets it as UNIX timestamp for expiration.
• bytes - This is the length of the data in bytes that needs to be stored in Memcached.
• noreply (optional) - This parameter informs the server not to send any reply.
• value - It is the data that needs to be stored. The data needs to be given on the new line after executing the command with the above options.

Example

• First we set a key (tutorials) and value (memcached) in Memcached
• Then, We retrieve the value using get command and check it
• Then, we prepend "redis" to the key tutorials
• and, we retrieve it and check again.

set tutorials 0 900 9
memcached
STORED
get tutorials
VALUE tutorials 0 14
memcached
END
prepend tutorials 0 900 5
redis
STORED
get tutorials
VALUE tutorials 0 14
redismemcached
END

Output

STORED

• STORED indicates success.
• NOT_STORED indicates the key does not exist in the Memcached server.
• CLIENT_ERROR indicates error.

Prepend Data Using Java Application

Example

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("tutorialspoint", 900, "Education for All");

         // print status of set method
         System.out.println("set status:" + fo.get());

         // retrieve and check the value from cache
         System.out.println("tutorialspoint value in cache - " + mcc.get("tutorialspoint"));

         // try to add data with existing key
         Future fo = mcc.prepend("tutorialspoint", 900, "Free ");

         // print status of set method
         System.out.println("prepend status:" + fo.get());
         
         // retrieve and check the value from cache
         System.out.println("tutorialspoint 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
tutorialspoint value in cache - Education for All
prepend status:true
tutorialspoint value in cache - Free Education for All

Memcached - CAS Command

Syntax

cas key flags exptime bytes unique_cas_token [noreply]

• key - It is the name of the unique key by which data is accessed.
• flags - It is the 32-bit unsigned integer that the server stores with the data provided by the user, and returns along with the data when the item is retrieved.
• exptime - It is the expiration time (seconds) of data stored in cache. A 0 value means "never expire", i.e. it should not be removed from the cache unless required. If the exptime is more than 30 days then Memcached interprets it as UNIX timestamp for expiration.
• bytes - This is the length of the data in bytes that needs to be stored in Memcached.
• unique_cas_token − It is a unique token number obtained from gets comamand.
• noreply (optional) - This parameter informs the server not to send any reply.
• value - It is the data that needs to be stored. The data needs to be given on the new line after executing the command with the above options.

Example

• Incorrect cas statement i.e. unique cas key missing
• casing a non-existing key
• add a key value item
• obtain unique cas key using gets command
• use cas and unique_cas_key to update data item
• use get command and check if data is updated

cas tp 0 900 9
ERROR             <− unique cas key missing

cas tp 0 900 9 2
memcached
NOT_FOUND         <− the key tp does not exist

set tp 0 900 9
memcached
STORED

gets tp
VALUE tp 0 9 1
memcached
END

cas tp 0 900 5 1
redis
STORED

get tp
VALUE tp 0 5
redis
END

Output

• STORED indicates success.
• ERROR indicates error while saving data or wrong syntax.
• EXISTS indicates that someone has modified the CAS data since last fetch.
• NOT_FOUND indicates that the key does not exist in the Memcached server.

CAS Using Java Application

Example

import java.net.InetSocketAddress;
import java.util.concurrent.Future;

import net.spy.memcached.CASValue;
import net.spy.memcached.CASResponse;
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("tutorialspoint", 900, "Free Education");

         // print status of set method
         System.out.println("set status:" + fo.get());
            
         // retrieve value stored for tutorialspoint from cache
         System.out.println("tutorialspoint value in cache - " + mcc.get("tutorialspoint"));

         // obtain CAS token value using gets method
         CASValue casValue = mcc.gets("tutorialspoint");

         // display CAS token value
         System.out.println("CAS token - " + casValue);

         // try to update data using memcached cas method
         CASResponse casresp = mcc.cas("tutorialspoint", casValue.getCas(), 900, "Largest Tutorials-Library");
         
         // display CAS Response
         System.out.println("CAS Response - " + casresp);

         // retrieve and check the value from cache
         System.out.println("tutorialspoint value in cache - " + mcc.get("tutorialspoint"));

         // Shutdowns the memcached client
         mcc.shutdown();
         
      }catch(Exception ex)
         System.out.println(ex.getMessage());
   }
}

Output

Connection to server successful.
set status:true
tutorialspoint value in cache - Free Education
CAS - {CasValue 34/Free Education}
CAS Response - OK
tutorialspoint value in cache - Largest Tutorials-Library