--- /dev/null
+## IMPORTANT NOTE ##
+
+This file contains installation instructions for the 8.x-1.x version of the
+Drupal Memcache module. Configuration differs between 8.x and 7.x versions
+of the module, so be sure to follow the 7.x instructions if you are configuring
+the 7.x-1.x version of this module!
+
+## REQUIREMENTS ##
+
+- PHP 5.5 or greater
+- Availability of a memcached daemon: http://memcached.org/
+- One of the two PECL memcache packages:
+ - http://pecl.php.net/package/memcache (recommended)
+ - http://pecl.php.net/package/memcached
+
+For more detailed instructions on installing a memcached daemon or either of the
+memcache PECL extensions, please see the documentation online at
+https://www.drupal.org/node/1131458 which includes links to external
+walk-throughs for various operating systems.
+
+## INSTALLATION ##
+
+These are the steps you need to take in order to use this software. Order
+is important.
+
+ 1. Make sure you have one of the PECL memcache packages installed.
+ 2. Enable the memcache module.
+ You need to enable the module in Drupal before you can configure it to run
+ as the default backend. This is so Drupal knows where to find everything.
+ 2. Edit settings.php to configure the servers, clusters and bins that memcache
+ is supposed to use. You do not need to set this if the only memcache backend
+ is localhost on port 11211. By default the main settings will be:
+ $settings['memcache']['servers'] = ['127.0.0.1:11211' => 'default'];
+ $settings['memcache']['bins'] = ['default' => 'default'];
+ $settings['memcache']['key_prefix'] = '';
+ 7. Edit settings.php to make memcache the default cache class, for example:
+ $settings['cache']['default'] = 'cache.backend.memcache';
+ 8. If you wish to arbitrarily send cache bins to memcache, then you can do the
+ following. E.g. for the cache_render bin:
+ $settings['cache']['bins']['render'] = 'cache.backend.memcache';
+
+## ADVANCED CONFIGURATION ##
+
+### Multiple memcache backends ###
+
+ $settings['memcache']['servers'] = [
+ '127.0.0.1:11211' => 'default', // Default host and port
+ '127.0.0.1:11212' => 'default', // Default host with port 11212
+ '127.0.0.2:11211' => 'default', // Default port, different IP
+ 'server1.com:11211' => 'default', // Default port with hostname
+ 'unix:///path/to/socket' => 'default', 'Unix socket'
+ ];
+
+### Multiple servers, bins and clusters ###
+
+ $settings['memcache'] = [
+ 'servers' = [
+ 'server1:port' => 'default',
+ 'server2:port' => 'default',
+ 'server3:port' => 'cluster1',
+ 'serverN:port' => 'clusterN',
+ 'unix:///path/to/socket' => 'clusterS',
+ ],
+ 'bins' => [
+ 'default' => 'default',
+ 'bin1' => 'cluster1',
+ 'binN' => 'clusterN',
+ 'binX' => 'cluster1',
+ 'binS' => 'clusterS',
+ ],
+ ];
+
+The bin/cluster/server model can be described as follows:
+
+- Servers are memcached instances identified by host:port.
+
+- Clusters are groups of servers that act as a memory pool. Each cluster can
+ contain one or more servers.
+
+- Multiple bins can be assigned to a cluster.
+
+- The default cluster is 'default'.
+
+- If a bin can not be found it will map to 'default'.
+
+### Stampede Protection ###
+
+Memcache includes stampede protection for rebuilding expired and invalid cache
+items. To enable stampede protection, add the following config in settings.php:
+
+$settings['memcache']['stampede_protection'] = TRUE;
+
+To avoid lock stampedes, it is important that you enable the memcache lock
+implementation when enabling stampede protection -- enabling stampede protection
+without enabling the Memcache lock implementation can cause worse performance.
+
+Only change the following values if you're sure you know what you're doing,
+which requires reading the memcachie.inc code.
+
+The value passed to lock_acquire, defaults to '15':
+ $conf['memcache_stampede_semaphore'] = 15;
+
+The value passed to lock_wait, defaults to 5:
+ $conf['memcache_stampede_wait_time'] = 5;
+
+The maximum number of calls to lock_wait() due to stampede protection during a
+single request, defaults to 3:
+ $conf['memcache_stampede_wait_limit'] = 3;
+
+When adjusting these variables, be aware that:
+ - there is unlikely to be a good use case for setting wait_time higher
+ than stampede_semaphore;
+ - wait_time * wait_limit is designed to default to a number less than
+ standard web server timeouts (i.e. 15 seconds vs. apache's default of
+ 30 seconds).
+
+### Prefixing ###
+
+If you want to have multiple Drupal installations share memcached instances,
+you need to include a unique prefix for each Drupal installation in the memcache
+config in settings.php:
+
+ $settings['memcache']['key_prefix'] = 'something_unique';
+
+### Key Hash Algorithm
+
+Note: if the length of your prefix + key + bin combine to be more than 250
+characters, they will be automatically hashed. Memcache only supports key
+lengths up to 250 bytes. You can optionally configure the hashing algorithm
+used, however sha1 was selected as the default because it performs quickly with
+minimal collisions.
+
+ $settings['memcache']['key_hash_algorithm'] = 'sha1';
+
+Visit http://www.php.net/manual/en/function.hash-algos.php to learn more about
+which hash algorithms are available.
+
+### Memcache Distribution ###
+
+To use this module with multiple memcached servers, it is important that you set
+the hash strategy to consistent. This is controlled in the PHP extension, not the
+Drupal module.
+
+If using PECL memcache:
+Edit /etc/php.d/memcache.ini (path may changed based on package/distribution) and
+set the following:
+memcache.hash_strategy=consistent
+
+You need to reload apache httpd after making that change.
+
+If using PECL memcached:
+Memcached options can be controlled in settings.php. Consistent distribution is
+the default in this case but could be set using:
+
+ $setting['memcache']['options'] = [
+ Memcached::OPT_DISTRIBUTION => Memcached::DISTRIBUTION_CONSISTENT,
+ ];
+
+## LOCKS ##
+
+Locks have not yet been implemented using the memcache module.
+
+## TROUBLESHOOTING ##
+
+PROBLEM:
+Error:
+Failed to set key: Failed to set key: cache_page-......
+
+SOLUTION:
+Upgrade your PECL library to PECL package (2.2.1) (or higher).
+
+WARNING:
+Zlib compression at the php.ini level and Memcache conflict.
+See http://drupal.org/node/273824
+
+## MEMCACHE ADMIN ##
+
+A module offering a UI for memcache is included. It provides aggregated and
+per-page statistics for memcache.
+
+## OTHER NOTES ##
+
+### Memcached PECL Extension Support ###
+
+We also support the Memcached PECL extension. This extension backends
+to libmemcached and allows you to use some of the newer advanced features in
+memcached 1.4.
+
+NOTE: It is important to realize that the memcache php.ini options do not impact
+the memcached extension, this new extension doesn't read in options that way.
+Instead, it takes options directly from Drupal. Because of this, you must
+configure memcached in settings.php. Please look here for possible options:
+
+https://secure.php.net/manual/en/memcached.constants.php
+
+An example configuration block is below, this block also illustrates our
+default options (selected through performance testing). These options will be
+set unless overridden in settings.php.
+
+ $settings['memcache']['options'] = [
+ Memcached::OPT_COMPRESSION => FALSE,
+ Memcached::OPT_DISTRIBUTION => Memcached::DISTRIBUTION_CONSISTENT,
+ ];
+
+These are as follows:
+
+ * Turn off compression, as this takes more CPU cycles than it's worth for most
+ users
+ * Turn on consistent distribution, which allows you to add/remove servers
+ easily
+
+Other options you could experiment with:
+ + Memcached::OPT_BINARY_PROTOCOL => TRUE,
+ * This enables the Memcache binary protocol (only available in Memcached
+ 1.4 and later). Note that some users have reported SLOWER performance
+ with this feature enabled. It should only be enabled on extremely high
+ traffic networks where memcache network traffic is a bottleneck.
+ Additional reading about the binary protocol:
+ https://raw.githubusercontent.com/memcached/old-wiki/master/MemcacheBinaryProtocol.wiki
+ Note: The information on the link above will eventually be ported to
+ the new wiki under https://github.com/memcached/memcached/wiki.
+
+ + Memcached::OPT_TCP_NODELAY => TRUE,
+ * This enables the no-delay feature for connecting sockets; it's been
+ reported that this can speed up the Binary protocol (see above). This
+ tells the TCP stack to send packets immediately and without waiting for
+ a full payload, reducing per-packet network latency (disabling "Nagling").
projects / yaffs-website / blobdiff