Enhance database connection management by introducing configurable pool settings and implementing a retry mechanism for transient connection issues. Updated Sequelize pool options to use environment variables for better flexibility and added a retry wrapper for initializing settings to handle connection timeouts gracefully.

backend/utils/syncDatabase.js

@@ -23,6 +23,27 @@ const queryWithTimeout = async (query, timeoutMs = 30000, description = 'Query')
     }
 };
 
+// Helper: Retry wrapper for transient pool/connection issues
+const runWithRetry = async (fn, { retries = 3, delayMs = 2000, description = 'operation' } = {}) => {
+    let lastError;
+    for (let attempt = 1; attempt <= retries; attempt++) {
+        try {
+            return await fn();
+        } catch (error) {
+            lastError = error;
+            const isAcquireTimeout = error?.name === 'SequelizeConnectionAcquireTimeoutError'
+                || error?.message?.includes('ConnectionAcquireTimeoutError')
+                || error?.message?.includes('Operation timeout');
+            if (!isAcquireTimeout || attempt === retries) {
+                throw error;
+            }
+            console.warn(`⚠️  ${description} fehlgeschlagen (AcquireTimeout). Retry ${attempt}/${retries} in ${delayMs}ms...`);
+            await new Promise(resolve => setTimeout(resolve, delayMs));
+        }
+    }
+    throw lastError;
+};
+
 // Helper: Prüft ob Tabelle existiert
 const tableExists = async (schema, tableName) => {
     try {
@@ -592,7 +613,10 @@ const syncDatabase = async () => {
         await syncModelsWithUpdates(models);
 
         console.log("Initializing settings...");
-        await initializeSettings();
+        await runWithRetry(
+            () => initializeSettings(),
+            { retries: 3, delayMs: 2000, description: 'initializeSettings' }
+        );
 
         console.log("Initializing types...");
         await initializeTypes();