MC-33788: Magento 2.3.3 Upgrade breakes Galera cluster

Author: rostyslav-hymon

setup/src/Magento/Setup/Model/Installer.php

@@ -817,6 +817,28 @@ public function declarativeInstallSchema(array $request)
         $this->getDeclarationInstaller()->installSchema($request);
     }
 
+    /**
+     * Clear memory tables
+     *
+     * Memory tables that used in old versions of Magento for indexing purposes should be cleaned
+     * Otherwise some supported DB solutions like Galeracluster may have replication error
+     * when memory engine will be switched to InnoDb
+     *
+     * @param SchemaSetupInterface $setup
+     * @return void
+     */
+    private function cleanMemoryTables(SchemaSetupInterface $setup)
+    {
+        $connection = $setup->getConnection();
+        $tables = $connection->getTables();
+        foreach ($tables as $table) {
+            $tableData = $connection->showTableStatus($table);
+            if (isset($tableData['Engine']) && $tableData['Engine'] === 'MEMORY') {
+                $connection->truncateTable($table);
+            }
+        }
+    }
+
     /**
      * Installs DB schema
      *
@@ -835,6 +857,7 @@ public function installSchema(array $request)
         $setup = $this->setupFactory->create($this->context->getResources());
         $this->setupModuleRegistry($setup);
         $this->setupCoreTables($setup);
+        $this->cleanMemoryTables($setup);
         $this->log->log('Schema creation/updates:');
         $this->declarativeInstallSchema($request);
         $this->handleDBSchemaData($setup, 'schema', $request);

setup/src/Magento/Setup/Test/Unit/Model/InstallerTest.php

@@ -326,9 +326,10 @@ public function testInstall(array $request, array $logMessages)
             $setup = $this->createMock(Setup::class);
             $table = $this->createMock(Table::class);
             $connection = $this->getMockBuilder(AdapterInterface::class)
-                ->setMethods(['getSchemaListener', 'newTable'])
+                ->setMethods(['getSchemaListener', 'newTable', 'getTables'])
                 ->getMockForAbstractClass();
             $connection->expects($this->any())->method('getSchemaListener')->willReturn($this->schemaListenerMock);
+            $connection->expects($this->once())->method('getTables')->willReturn([]);
             $setup->expects($this->any())->method('getConnection')->willReturn($connection);
             $table->expects($this->any())->method('addColumn')->willReturn($table);
             $table->expects($this->any())->method('setComment')->willReturn($table);