Basic commands for memcached installation, configuration, etc.

Basic commands for memcached (installation, uninstall, startup, configuration-related)

-P Listening Port
The IP address of the-l connection, the default is native
-D Start memcached service
-D Restart Restart memcached service
-D Stop|shutdown shut down the running memcached service
-D Install installation memcached service
-d Uninstall Uninstall memcached service
-U Run as (only valid when run as root)
-m maximum memory usage, in MB. Default 64MB

-Returns an error when M memory is exhausted instead of deleting the item
-C Maximum Simultaneous connection number, default is 1024
-F Block size growth factor, default is 1.25
-N Minimum allocation space, key+value+flags default is 48
-H Display Help

memcached the basic command ( when memcached is activated for memcached Managed data and its own running state-related commands ):

Command	Description	Example
Get	Reads a value	Get MyKey
Set	Set a key unconditionally	Set MyKey 0 60 5
Add	ADD a new key	Add Newkey 0 60 5
Replace	Overwrite existing Key	Replace key 0 60 5
Append	Append data to existing key	Append key 0 60 15
Prepend	Prepend data to existing key	Prepend Key 0 60 15
incr	Increments numerical key value by given number	INCR MyKey 2
Decr	Decrements numerical key value by given number	DECR MyKey 5
Delete	Deletes an existing key	Delete MyKey
Flush_all	Invalidate specific items immediately	Flush_all
	Invalidate all items in n seconds	Flush_all 900
Stats	Prints General statistics	Stats
	Prints Memory statistics	Stats Slabs
	Prints Memory statistics	Stats malloc
	Print Higher level allocation statistics	Stats items
	Stats Detail
	Stats sizes
	Resets statistics	Stats Reset
Version	Prints server version.	Version
Verbosity	Increases log level	Verbosity
Quit	Terminate Telnet session	Quit

Keywords for viewing information in Chinese and English tables

Pid	Memcache The process ID of the server
Uptime	Number of seconds the server has been running
Time	Server's current UNIX timestamp
Version	Memcache version
Pointer_size	The current operating system pointer size (32-bit system is typically 32bit)
Rusage_user	Cumulative user time for the process
Rusage_system	Cumulative system time of the process
Curr_items	The number of items currently stored by the server
Total_items	Total number of items stored since server startup
bytes	The number of bytes consumed by the current server storage items
Curr_connections	The number of connections currently open
Total_connections	Number of connections that have been opened since the server was started
Connection_structures	Number of connection constructs that the server assigns
Cmd_get	Get command (gets) the total number of requests
Cmd_set	Set command (save) number of total requests
Get_hits	Total Hit Count
Get_misses	Total missed Hits
Evictions	Number of items deleted to get free memory (the space allocated to memcache needs to be removed from the old items to get space allocated to new items)
Bytes_read	Total Read bytes (number of bytes requested)
Bytes_written	Total Bytes sent (result bytes)
Limit_maxbytes	Size of memory allocated to Memcache (bytes)
Threads	Current number of threads

The following is a simple test code that accesses the object data with the identifier ' MyKey ' in the code:

The code is as follows

Copy Code

<?php Contains memcached class files Require_once (' memcached-client.php '); Option settings $options = Array ( ' Servers ' => array (' 192.168.1.1:11211 '),//memcached service address, port, multiple array elements can be used to represent more than one memcached service ' Debug ' => true,//whether to turn on debug ' Compress_threshold ' => 10240,//compressed with more than the number of bytes of data ' Persistant ' => false//whether to use persistent connection ); Create a Memcached object instance $MC = new memcached ($options); Set the unique identifier used by this script $key = ' MyKey '; Writing objects to the memcached $MC->add ($key, ' some random strings '); $val = $MC->get ($key); echo "n". Str_pad (' $MC->add () ', 60, ' _ '). " n "; Var_dump ($val); Replace the object data value that has been written $MC->replace ($key, Array (' some ' => ' haha ', ' array ' => ' xxx ')); $val = $MC->get ($key); echo "n". Str_pad (' $MC->replace () ', 60, ' _ '). " n "; Var_dump ($val); Delete an object in memcached $MC->delete ($key); $val = $MC->get ($key); echo "n". Str_pad (' $MC->delete () ', 60, ' _ '). " n "; Var_dump ($val); ?>

is not very simple, in practical applications, the result set of the database query is usually saved to the memcached, the next visit directly from the memcached, and no longer do the database query operations, which can greatly reduce the burden of the database. The value after the SQL statement MD5 () is typically used as the unique identifier key. Below is an example of caching a database query result set using memcached (this code fragment immediately follows the example code above):

code is as follows

copy code

<?php $sql = ' SELECT * from users '; $key = MD5 ($sql);//memcached object identifier if (!) ( $datas = $MC->get ($key))) { //cached data is not obtained in memcached, then a database query is used to get the recordset. echo "n". Str_pad (' Read datas from MySQL. ', 60, ' _ '). " n "; $conn = mysql_connect (' localhost ', ' test ', ' test '); mysql_select_db (' Test '); $result = mysql_query ($sql); while ($row = Mysql_fetch_object ($result)) $datas [] = $row; //Save the result set data obtained in the database to memcached for use on the next visit. $MC->add ($key, $datas); } else { echo "n". Str_pad (' Read datas from memcached. ', 60, ' _ '). " n "; } Var_dump ($datas); ?

It can be seen that the use of memcached, you can reduce the database connection, query operations, the database load down, the speed of the script also improved.

OK, so memcached basic erection completed, if there is any problem or what I said wrong welcome to contact me