new calculation approach with unique sessions, new API endpoint to get list of active sessions, fix for UNDEF user, UI and Back to support certificate management still under development

README.md

@@ -162,6 +162,75 @@ Ensure `mod_rewrite`, `mod_proxy`, and `mod_proxy_http` are enabled.
 
 ---
 
+## 🧹 Database Management
+
+### Resetting Statistics
+To completely reset all traffic statistics and start fresh:
+
+1.  **Stop Services**:
+    ```bash
+    # Systemd
+    sudo systemctl stop ovpmon-gatherer ovpmon-api
+    
+    # OpenRC (Alpine)
+    rc-service ovpmon-gatherer stop
+    rc-service ovpmon-api stop
+    ```
+
+2.  **Remove Database**:
+    Navigate to the application directory (e.g., `/opt/ovpmon/APP`) and delete or rename the database file:
+    ```bash
+    rm openvpn_monitor.db
+    ```
+
+3.  **Restart Services**:
+    The system will automatically recreate the database with a fresh schema.
+    ```bash
+    # Systemd
+    sudo systemctl start ovpmon-gatherer ovpmon-api
+    
+    # OpenRC (Alpine)
+    rc-service ovpmon-gatherer start
+    rc-service ovpmon-api start
+    ```
+
+### Advanced: Reset Stats (Keep Client List)
+To reset counters but keep the known list of clients, run this SQL command:
+```bash
+sqlite3 openvpn_monitor.db "
+DELETE FROM usage_history;
+DELETE FROM stats_5min;
+DELETE FROM stats_15min;
+DELETE FROM stats_hourly;
+DELETE FROM stats_6h;
+DELETE FROM stats_daily;
+DELETE FROM active_sessions;
+UPDATE clients SET 
+    total_bytes_received = 0, 
+    total_bytes_sent = 0, 
+    last_bytes_received = 0, 
+    last_bytes_sent = 0,
+    status = 'Disconnected';
+VACUUM;"
+```
+
+### Remove a Specific User
+To completely remove a user (e.g., `UNDEF`) and their history:
+```bash
+sqlite3 openvpn_monitor.db "
+DELETE FROM usage_history WHERE client_id IN (SELECT id FROM clients WHERE common_name = 'UNDEF');
+DELETE FROM stats_5min WHERE client_id IN (SELECT id FROM clients WHERE common_name = 'UNDEF');
+DELETE FROM stats_15min WHERE client_id IN (SELECT id FROM clients WHERE common_name = 'UNDEF');
+DELETE FROM stats_hourly WHERE client_id IN (SELECT id FROM clients WHERE common_name = 'UNDEF');
+DELETE FROM stats_6h WHERE client_id IN (SELECT id FROM clients WHERE common_name = 'UNDEF');
+DELETE FROM stats_daily WHERE client_id IN (SELECT id FROM clients WHERE common_name = 'UNDEF');
+DELETE FROM active_sessions WHERE client_id IN (SELECT id FROM clients WHERE common_name = 'UNDEF');
+DELETE FROM clients WHERE common_name = 'UNDEF';
+VACUUM;"
+```
+
+---
+
 ## 📚 API Reference
 
 **Base URL:** `http://<server-ip>:5001/api/v1`