C # memcache

C # memcache
Memcache is an open-source distributed high-speed cache system. It is composed of a server and a client. It runs on one or more servers in the form of a daemon (listener) and receives client connections and operations at any time. Memcache caches data objects to the memory and maintains a unified and huge hash table in the memory. Simply put, the data is called to the memory and then read from the memory, which greatly improves the reading speed. Memcache stores objects to the memory based on the hashmap of a storage key/value pair. Memcache is written in C, but the client can be written in any language and communicate with the daemon through the memcached protocol. Feature: there is no limit on the data size of items that can be stored in Memcached, as long as the memory is sufficient. Memcached has a maximum memory usage of 2 GB for a single process in a 32-bit system. If it is in a 64-bit system, there is no limit. This is because a 32-bit system limits that a single process can use a maximum of 2 GB of memory, to use more memory, you can enable multiple Memcached processes on multiple ports. The data expiration time of up to 30 days. If it is set to permanent, the data will also expire at this time. The maximum data of a single item of the constant REALTIME_MAXDELTA is 1 MB. Data that exceeds 1 MB will not be stored, the constant POWER_BLOCK 1048576 is used to control the installation of Memcache in Windows. After learning about some basic information about memcache, you can try to install the memcache server in windows. First download the memcache Installation File: [installation package ]. The installation package contains two folders, x64and x86. you can find memcached.exe when selecting and logging from the operating system. This file cannot be installed by double-clicking it. You need to install it through cmd. Installation Steps: 1. window + R: Enter 2. 2. for G Disk: Input G: 3. run the following command to install Memcached for window 32/64: Enter cd CK \ memcached_en32or64 \ x644. install memcached: Enter memcached-d install5. start service: Enter memcached-d start to start the service. memcached-d start | stop | shutdown | restart | uninstall | install start | stop | restart | uninstall | install. The installation steps are not complex. First, find the file (memcached.exe) path. Second: memcached-d install on OK .. basic default parameter description: the IP address connected to Port-l of the-p listener, the default value is local-d start to start memcached service-d restart to restart memcached service-d stop | shutdown to disable the running memcached service-d install to install memcached service-d uninstall to uninstall memcached service-u run as (only valid when running as root) -MB maximum memory usage, in MB. By default, an error is returned when 64MB-M memory is used up, instead of deleting the maximum number of concurrent connections in item-c. The default value is 1024-f, and the default value is 1.25-n, key + value + flags is 48-h by default. After the server operation is completed, we can telnet to the service test box on the local machine. (If you are prompted that the telnet command does not exist, you need to go to the control panel to enable the windows tel service function. To enable the tel function for win7, follow these steps: [Control Panel]-> [program and function]-> [enable or disable the window function], and then find and check tel. The steps for other Windows systems are similar .) Test whether telnet runs normally. When telnet 172.21.0.192 11211 is enabled, press ctrl +] to start the display function. Otherwise, the input information cannot be displayed. After the callback function is successfully started, press enter to enter the stats parameter. The installation and testing are completed. The instance code has many C # version Memcached client programs. Here we use Memcached. clientLibrary. dll client call method. The call requires two DLL: Memcached. clientLibrary. dll (Memcached client class library) log4net. dll (log4net provides log records for Memcached) DLL: [Click to download] reference the two dll files in the project and reference log4net. after the dll, you also need to perform a series of configuration work. The configuration of log4net is introduced in the previous blog. [Log4Net log configuration [with source code] Note: Memcached. ClientLibrary. dll and log4net. dll have version ing. 2. If you use WinForm or the console application to display the log4net configuration file independently, you need to set it up in App. config. The Log4Net. config attribute "Copy to output directory": "Always copy ". Otherwise, an error is reported if the corresponding configuration information cannot be found in the bin directory. Memcache stores objects to the memory based on the hashmap of a storage key/value pair. Therefore, we can understand that key-value pairs are mainly used to operate hashmap. The following are some simple operations: [add, delete, modify, and query]: // set string SockIOPoolName = "Test_SockIOPoolName"; string [] MemcacheServiceList = {"172.21.0.192: 11211 "}; // set SockIOPool SPool = SockIOPool. getInstance (SockIOPoolName); SPool. setServers (MemcacheServiceList); SPool. initialize (); // instantiate ClientMemcachedClient MClient = new MemcachedClient (); MClient. poolName = SockIOPoolName; Console. writeLine ("1. create memcache cache Hello World "); MClient. Add ("Key1001", "Hello World"); Console. writeLine ("2. query Cache Information {0} ", MClient. get ("Key1001"); Console. writeLine ("3. modify memcache cache Hello World "); MClient. set ("Key1001", "Hello World-modified version"); Console. writeLine ("4. query Cache Information {0} ", MClient. get ("Key1001"); if (MClient. keyExists ("Key1001") {Console. writeLine ("5. delete memcache cache "); MClient. delete ("Key1001");} if (MClient. keyExists ("Key1001") Console. writeLine (MClient. ge T ("Key1001"); else Console. WriteLine ("6. Delete deleted"); Under Memcached distributed storage, assume that the memcached server has node1 ~ Three node3 applications need to save data with the keys "tokyo", "kanagawa", "CHBA", "saitama", and "gunma. First, add "tokyo" to memcached ". After "tokyo" is passed to the client library, the algorithm implemented by the client determines the memcached server that stores data based on the "key. After the server is selected, run the command to save "tokyo" and its value. Similarly, "kanagawa", "CHBA", "saitama", and "gunma" are both selected first and then saved. Next, obtain the saved data. The key "tokyo" to be obtained is also passed to the function library. The function library uses the same algorithm as the data storage algorithm to select a server based on the "key. If the algorithm used is the same, you can select the same server as the storage server and then send the get command. As long as the data is not deleted for some reason, you can get the saved value. In this way, memcached is distributed by storing different keys on different servers. When the number of memcached servers increases, keys will be dispersed. Even if a memcached server fails to connect, other caches will not be affected, and the system will continue to run. (Refer to: memcached full profiling) // parameter string [] MemcacheServiceList = {"172.21.0.192: 11211", "172.21.0.28: 11211", "172.21.13.246: 11211 "}; // set SockIOPool SPool = SockIOPool. getInstance (); SPool. setServers (MemcacheServiceList); SPool. initialize (); MemcachedClient MClient = new MemcachedClient (); MClient. flushAll (); int count = 5; var time = Stopwatch. startNew (); for (int I = 0; I <count; I ++) {MClient. add (I. toStrin G (), "value" + I);} Console. WriteLine ("memcached cache created successfully. Time consumed: {0} ", time. elapsedTicks); time = Stopwatch. startNew (); for (int I = 0; I <count; I ++) {if (MClient. keyExists (I. toString () {Console. writeLine ("key: {0 }. value: {1} ", I, MClient. get (I. toString ();} else {Console. writeLine ("-------- failed to query data key: {0} --------", I) ;}} Console. writeLine ("memcached cache data query is complete. Time consumed: {0} ", time. ElapsedTicks); SPool. Shutdown ();