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Memcached append command is used to add some data in an existing key. The data is stored after the existing data of the key.
Syntax
The basic syntax of Memcached append command is as shown below −
append key flags exptime bytes [noreply] value
The keywords in the syntax are as described below−
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key − It is the name of the key by which data is stored and retrieved from
Memcached. -
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.
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exptime − It is the expiration time in seconds. 0 means no delay. If exptime is more than 30 days, Memcached uses it as a UNIX timestamp for expiration.
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bytes − It is the number of bytes in the data block that needs to be stored. This is the length of the data that needs to be stored in Memcached.
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noreply (optional) − It is a parameter that informs the server not send any reply.
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value − It is the data that needs to be stored. The data needs to be passed on the new line after executing the command with the above options.
Output
The output of the command is as shown below −
STORED
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STORED indicates success.
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NOT_STORED indicates the key does not exist in the Memcached server.
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CLIENT_ERROR indicates error.
Example
In the following example, we try to add some data in a key that does not exist. Hence, Memcached returns NOT_STORED. After this, we set one key and append data into it.
append tutorials 0 900 5 redis NOT_STORED 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
Append Data Using Java Application
To append data in a Memcached server, you need to use the Memcached append method.
Example
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("tutorialspoint", 900, "memcached").isDone()); // Get value from cache System.out.println("Get from Cache:"+mcc.get("tutorialspoint")); // now append some data into existing key System.out.println("Append to cache:"+mcc.append("tutorialspoint", "redis").isDone()); // get the updated key System.out.println("Get from Cache:"+mcc.get("tutorialspoint")); } }
Output
On compiling and executing the program, you get to see the following output −
Connection to server successful set status:true Get from Cache:memcached Append to cache:true Get from Cache:memcachedredis
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