Enabling Memcached on Cloud Platform¶

To enable Memcached on your website hosted by Cloud Platform, you must install the Memcache API and Integration module in your codebase, and configure the module for use.

When configuring your website to use Memcached, be aware of the following considerations:

Do not edit the memcache_key_prefix or memcache_servers settings, as Cloud Platform adds the correct values in Acquia-specific code defined by the Acquia require line, or otherwise available by default on Cloud Next. Altering these values can cause unexpected behavior.
If your website uses either automated testing or the memcache_admin submodule, you must enable the Memcache API and Integration module. Although Drupal 9 or later does not require you to enable the module, Acquia recommends enabling the module to receive notifications about module updates.
For more information about stampede protection and database locking, see Enabling stampede protection and moving locks into memory.

Important

Test any of the procedures provided on this page on a non-production environment before implementing them on the production environment.
In Cloud Next, Acquia routinely optimizes the non-production environment to ensure high performance and enhanced scalability of your application. Therefore, your non-production memcache storage might be emptied from time to time. Production-level memcache workloads are notified in advance according to Acquia’s communication policies.

Configuration for Drupal 9 or later¶

For Memcached to function, you must provide additional configuration code that enables autoloading, and identifies Memcached as an alternative cache back-end.

To configure your website for Memcached, make the following changes to your codebase, depending on your subscription type:

Note

For environments running on Cloud Next technologies:

Memcache runs per-environment instead of per-server and leverages mcrouter. Steps 2 and 3 are not required because Memcache configuration logic is included automatically. To exclude this logic on your environments, add the following line to your settings.php file:
```
define('AH_NO_MEMCACHE_INCLUDE', 1);
```
If you have the older cloud-memcache-d8+.php file stored in this repository, ensure that you delete it.

Download the Memcache API and Integration module, and then add the module to your codebase in the modules/contrib/memcache directory. We recommend to use Composer to install the module:
```
composer require drupal/memcache
```
Add the composer package that contains the Acquia Memcache settings to your project:
```
composer require acquia/memcache-settings
```

For each website that requires Memcached, edit the Cloud Platform database require line in settings.php with a PHP require_once statement, similar to the following example:

if (file_exists('/var/www/site-php')) {
   require('/var/www/site-php/mysite/mysite-settings.inc');

   // Memcached settings for Acquia Hosting
   $memcache_settings_file = DRUPAL_ROOT . "/../vendor/acquia/memcache-settings/memcache.settings.php";
   if (file_exists($memcache_settings_file)) {
     require_once $memcache_settings_file;
   }
}

Rebuild caches by running the following command, replacing [example.com] with the domain name of your website:
```
drush cr --uri=[example.com]
```
Truncate all cache_ tables in the database for the website.

Memcache is now enabled for your website. Continue to read the next section.

If you need assistance, create a Support ticket.

Download the Memcache API and Integration module and add the module to your codebase in the modules/contrib/memcache directory. We recommend to use Composer to install the module:
```
composer require drupal/memcache
```
Download acsfd8+.memcache.settings.php, and then add it to the factory-hooks/post-settings-php directory. For more information about the post-settings-php hook, see Altering values in settings.php with hooks.
Rebuild caches by running the following command, replacing [example.com] with the domain name of your website:
```
drush cr --uri=[example.com]
```
Truncate all cache_ tables in the database for the website.

Memcache is now enabled for your website. If you need assistance, create a Support ticket.

For BLT users

BLT users that continue to experience issues should submit a ticket to the BLT issue queue.

Configuration for Drupal 7¶

If you are installing the module on a Drupal 7 website, you must enable the module before modifying settings.php, or you will receive a ServiceNotFoundException: error message.

Note

For Drupal 7 environments running on Cloud Next technologies, step 2 isn’t required because Memcache configuration logic is included automatically. To exclude this logic on your environments, add the following line to your settings.php file:

define('AH_NO_MEMCACHE_INCLUDE', 1);

To configure your Drupal 7 website for Memcached, make the following changes to your codebase, depending on your subscription type:

Download the Memcache API and Integration module, and then add the module to your codebase in the sites/all/modules/contrib/memcache directory.
Download cloud-memcache-d7.php, and add the contents of the file to your website’s settings.php file, after the Acquia database require line.
Clear caches by running the following command, replacing [example.com] with the domain name of your website:
```
drush cc all --uri=[example.com]
```
Truncate all cache_ tables in the database for the website.

Memcache is now enabled for your website. If you need assistance, create a Support ticket.

Download the Memcache API and Integration module, and then add the module to your codebase in the sites/all/modules/contrib/memcache directory.
Download acsfd7.memcache.settings.php, and add it to the factory-hooks/post-settings-php directory. For more information about the post-settings-php hook, see Altering values in settings.php with hooks.

Edit the file, modifying the following lines if they do not correspond to the location of the Memcache API and Integration module in your codebase:

$conf['cache_backends'][] = 'sites/all/modules/contrib/memcache/memcache.inc';

$conf['lock_inc'] = 'sites/all/modules/contrib/memcache/memcache-lock.inc';

Clear caches by running the following command , replacing [example.com] with the domain name of your website:
```
drush cc all --uri=[example.com]
```
Truncate all cache_ tables in the database for the website.

Memcache is now enabled for your website. Continue to read the next section.

If you need assistance, create a Support ticket.

Allocating memory to Memcached¶

Cloud Platform Enterprise¶

For environments running on Cloud Next technologies, you can adjust the memory allocated to Memcached by navigating to the Environment Settings page of the Cloud Platform user interface and selecting the Advanced tab.

For environments running on the Cloud Classic infrastructure, you must create a Support ticket to request that your Memcached memory allocation be modified. Larger amounts of memory can be allocated to Cloud Classic environments with dedicated Memcached infrastructure. Contact your Acquia account team for more information about this advanced configuration.

Cloud Platform Professional¶

To allocate memory to Memcached on Cloud Platform Professional and enable it to run:

Sign in to the Cloud Platform user interface and select your application and environment.
In the navigation pane, click Infrastructure.
In the card for the web infrastructure, click the Configure link.
In the Memcached memory (MB) field, enter the amount of memory to allocate to Memcached. A value of 64 MB is the default value for applications running on Cloud Platform, but you may increase the value depending on the needs of your application.
Click Save.

Using binary protocol¶

You can leverage the Memcache binary protocol in Cloud Classic environments. However, Acquia does not recommend its use.

To use this protocol in Cloud Classic environments, ensure that you enable the Memcached::OPT_TCP_NODELAY flag in Memcache options to avoid slow fetches of empty cache items.