Php Apc Vs Apcu
Xcache
Php Apcu Caching
Php Apc Extension

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APC is the Alternative PHP Cache. It’s a handy caching utility for use with PHP. We use it with W3 Total Cache on our WordPress installations. It runs OK “out of the box.”.
APC is a free, open, and robust framework for caching and optimizing PHP intermediate code. Latest Tarball Changelog.

Hi, Operating system: Ubuntu 20.04.1 LTS Plesk version: Plesk Obsidian v18.0.29build.19 I have already googled and tried all the existing guides but unfortunately none seem to work. So i kindly ask for help on how to install APC/APCu extension for PHP 7.4.x with Ubuntu 20.4.1 LTS.

The AWS SDK for PHP is able to send HTTP requests to various web services with minimal overhead. This document servesas a guide that will help you to achieve optimal performance with the SDK.

Using an up-to-date version of PHP will generally improve the performance ofyour PHP applications. Upgrading to PHP 5.5or greater will provide better performance and lower memory usage. If you cannotupgrade from PHP 5.3 to PHP 5.5 (or PHP 5.4), upgrading to the latest PHP 5.3.xwill improve performance over older versions of PHP 5.3.

You can install PHP 5.5 on an Amazon Linux AMI using the following command.

To improve the overall performance of your PHP environment, it is highly recommended that you use an opcode cachesuch as the OPCache built into PHP 5.5, APC, XCache, or WinCache. By default, PHP must load a file from disk, parsethe PHP code into opcodes, and finally execute the opcodes. Installing an opcode cache allows the parsed opcodes tobe cached in memory so that you do not need to parse the script on every web server request, and in idealcircumstances, these opcodes can be served directly from memory.

We have taken great care to ensure that the SDK will perform well in an environment that utilizes an opcode cache.

Note

PHP 5.5 comes with an opcode cache that is installed and enabled by default:http://php.net/manual/en/book.opcache.php

If you are using PHP 5.5, then you may skip the remainder of this section.

APC¶

If you are not able to run PHP 5.5, then we recommend using APC as an opcode cache.

Installing on Amazon Linux¶

When using Amazon Linux, you can install APC using one of the following commands depending on if you are using PHP 5.3or PHP 5.4.

Modifying APC settings¶

APC configuration settings can be set and configured in the apc.ini file of most systems. You can find moreinformation about configuring APC in the PHP.net APC documentation.

The APC configuration file is located at /etc/php.d/apc.ini on Amazon Linux.

apc.shm_size=128M¶

It is recommended that you set the apc.shm_sizesetting to be 128M or higher. You should investigate what the right value will be for your application. The idealvalue will depend on how many files your application includes, what other frameworks are used by your application, andif you are caching data in the APC user cache.

You can run the following command on Amazon Linux to set apc.shm_size to 128M:

apc.stat=0¶

The SDK adheres to PSR-0 and relies heavily on class autoloading. When apc.stat=1, APC will perform a stat oneach cached entry to ensure that the file has not been updated since it was cache in APC. This incurs a system call forevery autoloaded class required by a PHP script (you can see this for yourself by running strace on yourapplication).

Php Apc Vs Apcu

You can tell APC to not stat each cached file by setting apc.stat=0 in you apc.ini file. This change will generallyimprove the overall performance of APC, but it will require you to explicitly clear the APC cache when a cached fileshould be updated. This can be accomplished with Apache by issuing a hard or graceful restart. This restart step couldbe added as part of the deployment process of your application.

You can run the following command on Amazon Linux to set apc.stat to 0:

From the PHP documentation

This defaults to on, forcing APC to stat (check) the script on each request to determine if it has been modified. Ifit has been modified it will recompile and cache the new version. If this setting is off, APC will not check, whichusually means that to force APC to recheck files, the web server will have to be restarted or the cache will have tobe manually cleared. Note that FastCGI web server configurations may not clear the cache on restart. On a productionserver where the script files rarely change, a significant performance boost can be achieved by disabled stats.

For included/required files this option applies as well, but note that for relative path includes (any path thatdoesn't start with / on Unix) APC has to check in order to uniquely identify the file. If you use absolute pathincludes APC can skip the stat and use that absolute path as the unique identifier for the file.

Using Composer is the recommended way to install the AWS SDK for PHP. Composer is adependency manager for PHP that can be used to pull in all of the dependencies of the SDK and generate an autoloader.

Autoloaders are used to lazily load classes as they are required by a PHP script. Composer will generate an autoloaderthat is able to autoload the PHP scripts of your application and all of the PHP scripts of the vendors required by yourapplication (i.e. the AWS SDK for PHP). When running in production, it is highly recommended that you use a classmapautoloader to improve the autoloader's speed. You can generate a classmap autoloader by passing the -o or--optimize-autoloader option to Composer's install command:

Please consult the Installation guide for more information on how to install the SDK using Composer.

Xdebug is an amazing tool that can be used to identify performance bottlenecks. However, ifperformance is critical to your application, do not install the Xdebug extension on your production environment. Simplyloading the extension will greatly slow down the SDK.

When running on Amazon Linux, Xdebug can be removed with the following command:

The SDK utilizes URI templates to power each operation. In order to be compatible out of the box with the majorityof PHP environments, the default URI template expansion implementation is written in PHP.PECL URI_Template is a URI template extension for PHP written in C. This Cimplementation is about 3 times faster than the default PHP implementation for expanding URI templates. Yourapplication will automatically begin utilizing the PECL uri_template extension after it is installed.

The SDK utilizes service descriptions to tell the client how to serialize an HTTP request and parse an HTTP responseinto a Model object. Along with serialization information, service descriptions are used to validate operation inputsclient-side before sending a request. Disabling parameter validation is a micro-optimization, but this setting cantypically be disabled in production by setting the validation option in a client factory method to false.

When you do not provide credentials to the SDK and do not have credentials defined in your environment variables, theSDK will attempt to utilize IAM instance profile credentials by contacting the Amazon EC2 instance metadata service(IMDS). Contacting the IMDS requires an HTTP request to retrieve credentials from the IMDS.

You can cache these instance profile credentials in memory until they expire and avoid the cost of sending an HTTPrequest to the IMDS each time the SDK is utilized. Set the credentials.cache option to true to attempt toutilize the Doctrine Cache PHP library to cache credentials with APC.

Note

You will need to install Doctrine Cache in order for the SDK to cache credentials when settingcredentials.cache to true. You can add doctrine/cache to your composer.json dependencies by adding to yourproject's required section:

You can check to see if you are being throttled by enabling the exponential backoff logger option. You can set theclient.backoff.logger