diff --git a/app/init/resources.php b/app/init/resources.php
index 56cccab428..ce50c1bfea 100644
--- a/app/init/resources.php
+++ b/app/init/resources.php
@@ -907,11 +907,12 @@ Http::setResource('getDatabasesDB', function (Group $pools, Cache $cache, Docume
             $dsn = new DSN('mysql://' . $project->getAttribute('database'));
         }
 
-        $pool = $pools->get($databaseDSN->getHost());
+        $databaseHost = $databaseDSN->getHost();
+        $pool = $pools->get($databaseHost);
 
         $adapter = new DatabasePool($pool);
         $database = new Database($adapter, $cache);
-        $sharedTables = \explode(',', System::getEnv('_APP_DATABASE_SHARED_TABLES', ''));
+        $sharedTables = \array_filter(\explode(',', System::getEnv('_APP_DATABASE_SHARED_TABLES', '')));
 
         $database
             ->setDatabase(APP_DATABASE)
@@ -922,7 +923,28 @@ Http::setResource('getDatabasesDB', function (Group $pools, Cache $cache, Docume
             ->setMaxQueryValues(APP_DATABASE_QUERY_MAX_VALUES);
         // inside pools authorization needs to be set first
         $database->getAdapter()->setSupportForAttributes($databaseType !== DOCUMENTSDB);
-        if (\in_array($dsn->getHost(), $sharedTables)) {
+
+        // For separate pools (documentsdb/vectorsdb), check their own shared tables config.
+        // If not configured, use dedicated mode to avoid cross-engine tenant type mismatches.
+        if ($databaseHost !== $dsn->getHost()) {
+            $dbTypeSharedTables = match ($databaseType) {
+                DOCUMENTSDB => \array_filter(\explode(',', System::getEnv('_APP_DATABASE_DOCUMENTSDB_SHARED_TABLES', ''))),
+                VECTORSDB => \array_filter(\explode(',', System::getEnv('_APP_DATABASE_VECTORSDB_SHARED_TABLES', ''))),
+                default => [],
+            };
+
+            if (\in_array($databaseHost, $dbTypeSharedTables)) {
+                $database
+                    ->setSharedTables(true)
+                    ->setTenant($project->getSequence())
+                    ->setNamespace($dsn->getParam('namespace'));
+            } else {
+                $database
+                    ->setSharedTables(false)
+                    ->setTenant(null)
+                    ->setNamespace('_' . $project->getSequence());
+            }
+        } elseif (\in_array($dsn->getHost(), $sharedTables)) {
             $database
                 ->setSharedTables(true)
                 ->setTenant($project->getSequence())
diff --git a/app/worker.php b/app/worker.php
index bffc3b4b7e..fb624b4cb8 100644
--- a/app/worker.php
+++ b/app/worker.php
@@ -245,7 +245,8 @@ Server::setResource('getDatabasesDB', function (Cache $cache, Registry $register
         }
 
         $pools = $register->get('pools');
-        $pool = $pools->get($databaseDSN->getHost());
+        $databaseHost = $databaseDSN->getHost();
+        $pool = $pools->get($databaseHost);
 
         $adapter = new DatabasePool($pool);
         $database = new Database($adapter, $cache);
@@ -254,9 +255,27 @@ Server::setResource('getDatabasesDB', function (Cache $cache, Registry $register
             ->setAuthorization($authorization);
         $database->getAdapter()->setSupportForAttributes($databaseType !== DOCUMENTSDB);
 
-        $sharedTables = \explode(',', System::getEnv('_APP_DATABASE_SHARED_TABLES', ''));
+        $sharedTables = \array_filter(\explode(',', System::getEnv('_APP_DATABASE_SHARED_TABLES', '')));
 
-        if (\in_array($dsn->getHost(), $sharedTables, true)) {
+        if ($databaseHost !== $dsn->getHost()) {
+            $dbTypeSharedTables = match ($databaseType) {
+                DOCUMENTSDB => \array_filter(\explode(',', System::getEnv('_APP_DATABASE_DOCUMENTSDB_SHARED_TABLES', ''))),
+                VECTORSDB => \array_filter(\explode(',', System::getEnv('_APP_DATABASE_VECTORSDB_SHARED_TABLES', ''))),
+                default => [],
+            };
+
+            if (\in_array($databaseHost, $dbTypeSharedTables)) {
+                $database
+                    ->setSharedTables(true)
+                    ->setTenant($projectDocument->getSequence())
+                    ->setNamespace($dsn->getParam('namespace'));
+            } else {
+                $database
+                    ->setSharedTables(false)
+                    ->setTenant(null)
+                    ->setNamespace('_' . $projectDocument->getSequence());
+            }
+        } elseif (\in_array($dsn->getHost(), $sharedTables, true)) {
             $database
                 ->setSharedTables(true)
                 ->setTenant($projectDocument->getSequence())
diff --git a/src/Appwrite/Platform/Modules/Databases/Http/Databases/Create.php b/src/Appwrite/Platform/Modules/Databases/Http/Databases/Create.php
index 3585bc4477..3d07c65250 100644
--- a/src/Appwrite/Platform/Modules/Databases/Http/Databases/Create.php
+++ b/src/Appwrite/Platform/Modules/Databases/Http/Databases/Create.php
@@ -61,16 +61,16 @@ class Create extends Action
                 $databaseKeys = System::getEnv('_APP_DATABASE_DOCUMENTSDB_KEYS', '');
                 $databaseOverride = System::getEnv('_APP_DATABASE_DOCUMENTSDB_OVERRIDE');
                 $dbScheme = System::getEnv('_APP_DB_HOST_DOCUMENTSDB', 'mongodb');
-                $databaseSharedTables = \explode(',', System::getEnv('_APP_DATABASE_DOCUMENTSDB_SHARED_TABLES', ''));
-                $databaseSharedTablesV1 = \explode(',', System::getEnv('_APP_DATABASE_DOCUMENTSDB_SHARED_TABLES_V1', ''));
+                $databaseSharedTables = \array_filter(\explode(',', System::getEnv('_APP_DATABASE_DOCUMENTSDB_SHARED_TABLES', '')));
+                $databaseSharedTablesV1 = \array_filter(\explode(',', System::getEnv('_APP_DATABASE_DOCUMENTSDB_SHARED_TABLES_V1', '')));
                 break;
             case VECTORSDB:
                 $databases = Config::getParam('pools-vectorsdb', []);
                 $databaseKeys = System::getEnv('_APP_DATABASE_VECTORSDB_KEYS', '');
                 $databaseOverride = System::getEnv('_APP_DATABASE_VECTORSDB_OVERRIDE');
                 $dbScheme = System::getEnv('_APP_DB_HOST_VECTORSDB', 'postgresql');
-                $databaseSharedTables = \explode(',', System::getEnv('_APP_DATABASE_VECTORSDB_SHARED_TABLES', ''));
-                $databaseSharedTablesV1 = \explode(',', System::getEnv('_APP_DATABASE_VECTORSDB_SHARED_TABLES_V1', ''));
+                $databaseSharedTables = \array_filter(\explode(',', System::getEnv('_APP_DATABASE_VECTORSDB_SHARED_TABLES', '')));
+                $databaseSharedTablesV1 = \array_filter(\explode(',', System::getEnv('_APP_DATABASE_VECTORSDB_SHARED_TABLES_V1', '')));
                 break;
             default:
                 // legacy/tablesdb
@@ -108,7 +108,7 @@ class Create extends Action
         if ($index !== false) {
             $selectedDsn = $databases[$index];
         } else {
-            if (!empty($dsn)) {
+            if (!empty($dsn) && !empty($databaseSharedTables)) {
                 $beforeFilter = \array_values($databases);
                 if ($isSharedTablesV1) {
                     $databases = array_filter($databases, fn ($value) => \in_array($value, $databaseSharedTablesV1));
@@ -118,7 +118,10 @@ class Create extends Action
                     $databases = array_filter($databases, fn ($value) => !\in_array($value, $databaseSharedTables));
                 }
             }
-            $selectedDsn = !empty($databases) ? $databases[array_rand($databases)] : '';
+            if (empty($databases)) {
+                throw new Exception(Exception::GENERAL_SERVER_ERROR, "No {$databasetype} database pool available for the current shared-tables mode");
+            }
+            $selectedDsn = $databases[array_rand($databases)];
         }
 
         if (\in_array($selectedDsn, $databaseSharedTables)) {