Installing Memcached on Windows
Memcached is a high performance, in-memory key-value store or caching system. Its main purpose is to speed up web applications by caching database queries, contents, or other computed results.
Memcached is originally a linux application, but since it is open-source, it has been compiled for windows. There are two major sources for the pre-built windows binary: Jellycan and Northscale, and both versions can be used. The following are the download links for the memcached windows binaries:
http://code.jellycan.com/files/memcached-1.2.5-win32-bin.zip
http://code.jellycan.com/files/memcached-1.2.6-win32-bin.zip
http://downloads.northscale.com/memcached-win32-1.4.4-14.zip
http://downloads.northscale.com/memcached-win64-1.4.4-14.zip
http://downloads.northscale.com/memcached-1.4.5-x86.zip
http://downloads.northscale.com/memcached-1.4.5-amd64.zip
In versions earlier than 1.4.5, memcached can install itself as a service. However, the ability to run memcached as a service is removed since version 1.4.5. Therefore, the installation steps are divided into two categories, part A for memcached prior to version 1.4.5. and part B for memcached version 1.4.5 and later.
A) Installation of memcached < 1.4.5:
- Extract the memcached windows binary to any directory.
- In versions earlier than 1.4.5, memcached can install itself as a service. Run a command prompt with elevated privileges, and type:
c:\memcached\memcached.exe -d install
* Replace c:\memcached\memcached.exe with the actual path of your installation.
- Then, start or stop the memcached service with the following command:
c:\memcached\memcached.exe -d start
c:\memcached\memcached.exe -d stop - To change the configuration of memcached, run regedit.exe and navigate to the key "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\memcached". Suppose you wish to increase the memory limit of memcached, edit the value of ImagePath to the following:
"c:\memcached\memcached.exe" -d runservice -m 512
* Besides '-m 512', you may also append other memcached parameters to the path. Run "c:\memcached\memcached.exe -h" to view the list of available parameters.
- Meanwhile, to uninstall the memcached serivce, run the following command:
c:\memcached\memcached.exe -d uninstall
B) Installation of memcached >= 1.4.5:
- Extract the memcached windows binary to any directory.
- In version 1.4.5 or later, memcached cannot run as a service. It must be started as a normal process using the task scheduler. To configure the memcached process to run automatically every time windows start, run a command prompt with elevated privileges, and type the following:
schtasks /create /sc onstart /tn memcached /tr "'c:\memcached\memcached.exe' -m 512"
* Replace c:\memcached\memcached.exe with the actual path of your installation.
** Besides '-m 512', you may also append other memcached parameters to the path. Run "c:\memcached\memcached.exe -h" to view the list of available parameters. - Meanwhile, to remove the scheduled memcached task, run the following command:
schtasks /delete /tn memcached
Integrating with PHP
To interface with memcached in PHP, you need to install the memcache extension for PHP:
- Check that your PHP extension folder has the file php_memcache.dll. If not, download the file from https://pecl.php.net/package/memcache (select the windows dll file), and place it in the PHP extension folder.
- Add the following line in php.ini to enable the memcache extension.
extension=php_memcache.dll - Create this simple php script file to test that it works.
<?php $memcache = new Memcache;
$memcache->connect('localhost', 11211) or die ("Could not connect"); $version = $memcache->getVersion();
echo "Server's version: ".$version."<br/>\n"; $tmp_object = new stdClass;
$tmp_object->str_attr = 'test';
$tmp_object->int_attr = 123; $memcache->set('key', $tmp_object, false, 10) or die ("Failed to save data at the server");
echo "Store data in the cache (data will expire in 10 seconds)<br/>\n"; $get_result = $memcache->get('key');
echo "Data from the cache:<br/>\n"; var_dump($get_result); ?>
Integrating with Python
To interface with memcached in Python, you need to install the memcached client for Python.
- Execute one of the following command to install the memcached client. The first is for Python 2.x while the second is for Python 3.x.
pip install python-memcached
pip install python3-memcached - Create this simple python script to test that it works.
import memcache
mc = memcache.Client(['127.0.0.1:11211'], debug=0)
mc.set("some_key", "Some value")
value = mc.get("some_key")
mc.set("another_key", 3)
mc.delete("another_key")
mc.set("key", "1") # note that the key used for incr/decr must be a string.
mc.incr("key")
mc.decr("key")
Memcached statistics
To view the statistics for memcached, bring up a telnet connection to memcached by the command:
telnet 127.0.0.1 11211
Then, type stats and enter.
Here is an explanation of the different memcached stats.
| Name | Type | Meaning |
|---|---|---|
| pid | 32u | Process id of this server process |
| uptime | 32u | Number of secs since the server started |
| time | 32u | current UNIX time according to the server |
| version | string | Version string of this server |
| pointer_size | 32 | Default size of pointers on the host OS (generally 32 or 64) |
| rusage_user | 32u.32u | Accumulated user time for this process (seconds:microseconds) |
| rusage_system | 32u.32u | Accumulated system time for this process (seconds:microseconds) |
| curr_items | 32u | Current number of items stored |
| total_items | 32u | Total number of items stored since the server started |
| bytes | 64u | Current number of bytes used to store items |
| curr_connections | 32u | Number of open connections |
| total_connections | 32u | Total number of connections opened since the server started running |
| connection_structures | 32u | Number of connection structures allocated by the server |
| reserved_fds | 32u | Number of misc fds used internally |
| cmd_get | 64u | Cumulative number of retrieval reqs |
| cmd_set | 64u | Cumulative number of storage reqs |
| cmd_flush | 64u | Cumulative number of flush reqs |
| cmd_touch | 64u | Cumulative number of touch reqs |
| get_hits | 64u | Number of keys that have been requested and found present |
| get_misses | 64u | Number of items that have been requested and not found |
| delete_misses | 64u | Number of deletions reqs for missing keys |
| delete_hits | 64u | Number of deletion reqs resulting in an item being removed. |
| incr_misses | 64u | Number of incr reqs against missing keys. |
| incr_hits | 64u | Number of successful incr reqs. |
| decr_misses | 64u | Number of decr reqs against missing keys. |
| decr_hits | 64u | Number of successful decr reqs. |
| cas_misses | 64u | Number of CAS reqs against missing keys. |
| cas_hits | 64u | Number of successful CAS reqs. |
| cas_badval | 64u | Number of CAS reqs for which a key was found, but the CAS value did not match. |
| touch_hits | 64u | Numer of keys that have been touched with a new expiration time |
| touch_misses | 64u | Numer of items that have been touched and not found |
| auth_cmds | 64u | Number of authentication commands handled, success or failure. |
| auth_errors | 64u | Number of failed authentications. |
| evictions | 64u | Number of valid items removed from cache to free memory for new items |
| reclaimed | 64u | Number of times an entry was stored using memory from an expired entry |
| bytes_read | 64u | Total number of bytes read by this server from network |
| bytes_written | 64u | Total number of bytes sent by this server to network |
| limit_maxbytes | 32u | Number of bytes this server is allowed to use for storage. |
| threads | 32u | Number of worker threads requested. (see doc/threads.txt) |
| conn_yields | 64u | Number of times any connection yielded to another due to hitting the -R limit. |
| hash_power_level | 32u | Current size multiplier for hash table |
| hash_bytes | 64u | Bytes currently used by hash tables |
| hash_is_expanding | bool | Indicates if the hash table is being grown to a new size |
| expired_unfetched | 64u | Items pulled from LRU that were never touched by get/incr/append/etc before expiring |
| evicted_unfetched | 64u | Items evicted from LRU that were never touched by get/incr/append/etc. |
| slab_reassign_running | bool | If a slab page is being moved |
| slabs_moved | 64u | Total slab pages moved |
| crawler_reclaimed | 64u | Total items freed by LRU Crawler |
| lrutail_reflocked | 64u | Times LRU tail was found with active ref. Items moved to head to avoid OOM errors. |
| Name | Type | Meaning |
Source: https://github.com/memcached/memcached/blob/master/doc/protocol.txt
另，*：
http://*.com/questions/8896/can-i-get-memcached-running-on-a-windows-x64-64bit-environment
North Scale labs have released a build of memcached 1.4.4 for Windows x64:
http://blog.couchbase.com/memcached-windows-64-bit-pre-release-available
http://labs.northscale.com/memcached-packages/
UPDATE: they have recently released Memcached Server - still FREE but enhanced distro with clustering, web-based admin/stats UI etc. (I'm not related to them in any way) Check it out at http://northscale.com/products/memcached.html and download at: http://www.northscale.com/download.php?a=d
UPDATE 2: NorthScale Memcached is no longer available as a standalone download. Now they have made it part of their commercial No-SQL DB offering called Membase. It can be configured to run in Memcached-only mode (i.e. without persistence) and there's a 100% free version too. Check it out here: http://www.membase.org/downloads
UPDATE 3: MemBase has slept with CouchDB and produced a hybrid product offering, called CouchBase. They still do offer a free "Community" version at http://www.couchbase.com/download