feat: Enhance ClickHouse client with improved session management and error handling

src/db/db_connection.py

@@ -9,17 +9,20 @@ from dotenv import load_dotenv
 # Load environment variables from .env file
 load_dotenv()
 
+# Configure logging
+logging.basicConfig(level=logging.INFO)
+logger = logging.getLogger(__name__)
+
 def create_client():
     """
-    Create a ClickHouse client with a unique session and retry logic,
-    using the password loaded from environment variables.
+    Create a ClickHouse client with enhanced session management and retry logic
     """
     clickhouse_password = os.getenv("CLICKHOUSE_PASSWORD")
     if not clickhouse_password:
         raise ValueError("CLICKHOUSE_PASSWORD environment variable not set.")
 
-    max_retries = 5  # Increased from 3 to 5
-    retry_delay = 1  # Reduced initial delay to 1 second
+    max_retries = 5
+    retry_delay = 1
     
     last_exception = None
     
@@ -36,32 +39,49 @@ def create_client():
                 secure=True,
                 session_id=session_id,
                 settings={
-                    'session_timeout': 60,
-                    'session_check': 1
-                }
+                    'session_timeout': 3600,  # Increased to 1 hour
+                    'session_check': 1,
+                    'keep_alive_timeout': 3600  # Added keep-alive timeout
+                },
+                connect_timeout=10,  # Added explicit connect timeout
+                send_receive_timeout=300  # Added send/receive timeout
             )
             
-            # Test the connection
-            client.query('SELECT 1')
-            return client
+            # Test the connection with a simple query
+            try:
+                client.query('SELECT 1')
+                logger.info(f"Successfully established connection with session {session_id}")
+                return client
+            except Exception as e:
+                if "SESSION_NOT_FOUND" in str(e) or "SESSION_IS_LOCKED" in str(e):
+                    raise  # Re-raise these specific errors to trigger retry
+                logger.error(f"Connection test failed: {str(e)}")
+                raise
             
         except Exception as e:
             last_exception = e
+            error_message = str(e)
             
-            # Check specifically for session locked error
-            if "SESSION_IS_LOCKED" in str(e):
+            # Handle specific error codes
+            if "SESSION_NOT_FOUND" in error_message:
                 if attempt < max_retries - 1:
-                    # Use exponential backoff for session locks
                     wait_time = retry_delay * (2 ** attempt)
-                    logging.warning(f"Session locked, retrying in {wait_time} seconds...")
+                    logger.warning(f"Session not found, retrying in {wait_time} seconds...")
                     time.sleep(wait_time)
                     continue
+            elif "SESSION_IS_LOCKED" in error_message:
+                if attempt < max_retries - 1:
+                    wait_time = retry_delay * (2 ** attempt)
+                    logger.warning(f"Session locked, retrying in {wait_time} seconds...")
+                    time.sleep(wait_time)
+                    continue
+            else:
+                # For other errors, use normal retry logic
+                if attempt < max_retries - 1:
+                    logger.warning(f"Connection attempt {attempt + 1} failed: {error_message}")
+                    time.sleep(retry_delay)
+                    continue
             
-            # For other errors, use normal retry logic
-            elif attempt < max_retries - 1:
-                logging.warning(f"Connection attempt {attempt + 1} failed: {str(e)}")
-                time.sleep(retry_delay)
-                continue
-            
-            # If we've exhausted all retries, raise the last exception
+            # If we've exhausted all retries, log the final error and raise
+            logger.error(f"Failed to establish connection after {max_retries} attempts: {error_message}")
             raise last_exception