What are the possible ways through which all caches can be disabled?

Question

In one of our project website started loading very slow and I found out all caches were disabled which I have enabled earlier.

I can figure out the following ways through which caches can get disabled:

• When someone runs php bin/magento cache:disable command.
• When someone modifies app/etc/env.php and disables caches from there.
• Under certain circumstances a file .regenerate is written in the var folder (either at setup upgrade or composer install / upgrade) and if that file is present when running php bin/magento setup:di:compile the cache is disabled and re-enabled when the compilation process is finished. For some reason, sometimes the cache is not re-enabled. (Referenced from here)

What are the other possibilities through which

• Someone having code/db access can disable it ?
• Automatically it can get disabled ?

Answer 1

In developer mode the option on backend is available to disable any cache from backend

Whereas in production mode, this option is not available, so you need to do it by command.

To disable all cache you need to run this as you already added in question:

php bin/magento cache:disable

And if you need to disable on cache, then disable it by it's tag name

Example:

magento cache:disable full_page

There is no database entry for these cache types, if you disable any cache from command, then it will update entry in env.php, and if you do it from admin then this method will also update entry in env.php

You wont find any other way to disable cache. You can disable it either from shell or from admin or directly from env.php

Hope this is the answer of your question.

Answer 2

This is known issue in Magento 2.2: https://github.com/magento/magento2/issues/17634

In this path: magento2/lib/internal/Magento/Framework/Code/GeneratedFiles.php. This is the code which disables the cache other than scenarios you mentioned in your answer

$deploymentConfig = $this->directoryList->getPath(DirectoryList::CONFIG);
            $configPool = new ConfigFilePool();
            $envPath = $deploymentConfig . '/' . $configPool->getPath(ConfigFilePool::APP_ENV);
            if ($this->write->isExist($this->write->getRelativePath($envPath))) {
                $enabledCacheTypes = $this->getEnabledCacheTypes();
                $this->disableAllCacheTypes();
            }

I hope this will help