MC-31920: Let Magento\Framework\Lock\Backend\Database have 2 locks in single connection

Author: adifucan

app/code/Magento/Config/etc/di.xml

@@ -96,7 +96,7 @@
 
     <virtualType name="systemConfigQueryLocker" type="Magento\Framework\Cache\LockGuardedCacheLoader">
         <arguments>
-            <argument name="locker" xsi:type="object">Magento\Framework\Lock\Backend\Cache</argument>
+            <argument name="locker" xsi:type="object">Magento\Framework\Lock\Backend\Database</argument>
         </arguments>
     </virtualType>
 

app/etc/di.xml

@@ -1786,7 +1786,7 @@
     </type>
     <type name="Magento\Framework\Cache\LockGuardedCacheLoader">
         <arguments>
-            <argument name="locker" xsi:type="object">Magento\Framework\Lock\Backend\Cache</argument>
+            <argument name="locker" xsi:type="object">Magento\Framework\Lock\Backend\Database</argument>
         </arguments>
     </type>
     <preference for="Magento\Framework\HTTP\AsyncClientInterface" type="Magento\Framework\HTTP\AsyncClient\GuzzleAsyncClient" />

lib/internal/Magento/Framework/Lock/Backend/Database.php

@@ -78,20 +78,6 @@ public function lock(string $name, int $timeout = -1): bool
         }
         $name = $this->addPrefix($name);
 
-        /**
-         * Before MySQL 5.7.5, only a single simultaneous lock per connection can be acquired.
-         * This limitation can be removed once MySQL minimum requirement has been raised,
-         * currently we support MySQL 5.6 way only.
-         */
-        if ($this->currentLock) {
-            throw new AlreadyExistsException(
-                new Phrase(
-                    'Current connection is already holding lock for %1, only single lock allowed',
-                    [$this->currentLock]
-                )
-            );
-        }
-
         $result = (bool)$this->resource->getConnection()->query(
             "SELECT GET_LOCK(?, ?);",
             [$name, $timeout < 0 ? self::MAX_LOCK_TIME : $timeout]