connection_broke_fix

controller.py

@@ -226,9 +226,13 @@ class ConnectionPoolManager:
                 self._pg_pools[db_url] = pg_pool.ThreadedConnectionPool(1, 10, **db_config)
         return self._pg_pools[db_url].getconn()
 
-    def return_postgres_connection(self, db_url, conn):
+    def return_postgres_connection(self, db_url, conn, close=False):
+        """
+        Returns connection to pool. 
+        If close=True, the connection is discarded (used for dead connections).
+        """
         if db_url in self._pg_pools and conn:
-            self._pg_pools[db_url].putconn(conn)
+            self._pg_pools[db_url].putconn(conn, close=close)
 
 pool_manager = ConnectionPoolManager()
 
@@ -318,6 +322,9 @@ def _run_mysql_synchronously(db_url: str, sql_query: str, max_rows: int = 20, li
     connection = None
     cursor = None
     response = {"success": False, "results": None, "columns": None, "rowCount": 0, "executionTime": 0.0, "error": None, "is_aggregate": False, "limited": False, "message": ""}
+    
+    # Flag for bad connections
+    connection_broken = False
 
     try:
         connection = pool_manager.get_mysql_connection(db_url)
@@ -361,17 +368,36 @@ def _run_mysql_synchronously(db_url: str, sql_query: str, max_rows: int = 20, li
         return response
 
     except Exception as e:
+        # Detect broken pipe or connection lost errors in MySQL
+        err_str = str(e).lower()
+        if "lost connection" in err_str or "gone away" in err_str or isinstance(e, mysql.connector.errors.OperationalError):
+            connection_broken = True
+        
         response["error"] = str(e)
         return response
     finally:
-        if cursor: cursor.close()
-        if connection: connection.close() # Returns to pool
+        try:
+            if cursor: cursor.close()
+        except: pass
+        
+        if connection:
+            if connection_broken:
+                # Discard dead connection (do NOT return to pool)
+                try: connection.close() 
+                except: pass
+            else:
+                # Return healthy connection to pool
+                connection.close() 
 
 def _run_postgres_synchronously(db_url: str, sql_query: str, max_rows: int = 20, limited: bool = False) -> dict:
     start_time = time.time()
     connection = None
     cursor = None
     response = {"success": False, "results": None, "columns": None, "rowCount": 0, "executionTime": 0.0, "error": None, "is_aggregate": False, "limited": False, "message": ""}
+    
+    # Flag to determine if connection is dead
+    connection_broken = False 
+
     try:
         connection = pool_manager.get_postgres_connection(db_url)
         cursor = connection.cursor(cursor_factory=RealDictCursor)
@@ -413,12 +439,27 @@ def _run_postgres_synchronously(db_url: str, sql_query: str, max_rows: int = 20,
         response.update({"success": True, "results": clean_results, "columns": columns, "rowCount": len(results), "executionTime": time.time() - start_time})
         return response
     except Exception as e:
-        if connection: connection.rollback()
+        # Detect fatal connection errors
+        err_msg = str(e).lower()
+        if "closed" in err_msg or "terminat" in err_msg or isinstance(e, (psycopg2.InterfaceError, psycopg2.OperationalError)):
+            connection_broken = True 
+        
+        if connection and not connection_broken:
+            try:
+                connection.rollback()
+            except Exception:
+                connection_broken = True 
+
         response["error"] = str(e)
         return response
     finally:
-        if cursor: cursor.close()
-        if connection: pool_manager.return_postgres_connection(db_url, connection)
+        try: 
+            if cursor: cursor.close()
+        except: pass
+        
+        if connection: 
+            # If broken, set close=True to discard it from pool
+            pool_manager.return_postgres_connection(db_url, connection, close=connection_broken)
 
 
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