Error
Error Code:
ORA-29276
Oracle ORA-29276: Transfer Timeout
Description
The ORA-29276 error indicates a transfer timeout during network communication within Oracle Database. This typically occurs when the database server is unable to read from or write to a remote server within the configured timeout period, interrupting data transfer.
Error Message
ORA-29276: transfer timeout
Known Causes
4 known causesRemote Server Unresponsive
The remote server may be down, overloaded, or experiencing network issues, preventing it from responding within the expected timeframe.
Network Connectivity Issues
Network problems such as packet loss, firewall restrictions, or routing issues can interrupt communication between the Oracle database server and the remote server.
Firewall Restrictions
A firewall may be blocking the connection between the Oracle database server and the remote server, leading to a timeout.
Insufficient Timeout Value
The configured timeout value in Oracle may be too short for the remote server to respond, especially if the server is under heavy load or the network latency is high.
Solutions
3 solutions available1. Increase UTL_TCP Timeout Parameters medium
Adjust the default timeout for UTL_TCP operations within the Oracle database.
1
Connect to the Oracle database as a user with DBA privileges.
2
Execute the following SQL statements to increase the `tcp_connect_timeout` and `tcp_receive_timeout` parameters. The values below are examples; adjust them based on your network latency and data transfer sizes. It's often recommended to start with values like 600 seconds (10 minutes) or higher.
ALTER SYSTEM SET "tcp_connect_timeout"=600 SCOPE=BOTH;
ALTER SYSTEM SET "tcp_receive_timeout"=600 SCOPE=BOTH;3
Restart the Oracle listener and database instance for the changes to take effect.
2. Investigate Network Connectivity and Latency advanced
Diagnose and resolve underlying network issues causing slow or interrupted data transfers.
1
From the database server, use `ping` to check latency and packet loss to the remote host involved in the transfer. If `ping` is not available or shows issues, use `traceroute` (Linux/macOS) or `tracert` (Windows) to identify network hops with high latency or packet loss.
ping <remote_host_ip_or_hostname>
traceroute <remote_host_ip_or_hostname>2
On the remote host, perform similar network tests back to the database server.
ping <database_server_ip_or_hostname>
traceroute <database_server_ip_or_hostname>3
Check firewall rules on both the database server and the remote host, as well as any intermediate network devices, to ensure they are not blocking or throttling traffic on the relevant ports (e.g., 1521 for Oracle listener, or custom ports used by UTL_TCP).
4
If using SSL/TLS for the transfer, verify that the SSL handshake and encryption/decryption processes are not causing significant delays.
5
If the transfer involves large amounts of data, consider network bandwidth limitations and potential congestion. Consult with your network administrators.
3. Optimize PL/SQL Code and Data Transfer Logic medium
Review and refine the PL/SQL code that utilizes UTL_TCP to ensure efficient data handling.
1
Analyze the PL/SQL code that calls `UTL_TCP`. Look for opportunities to reduce the number of network round trips. Batching data where possible can significantly improve performance.
2
Ensure that data is being read and written in reasonably sized chunks. Reading or writing excessively large or small amounts of data can be inefficient. Experiment with different buffer sizes.
3
If the transfer involves complex data structures, consider serializing/deserializing them efficiently. For example, using JSON or XML parsing libraries might be more efficient than manual string manipulation.
4
Profile the PL/SQL code to identify specific operations that are taking a long time. Use `DBMS_PROFILER` or `DBMS_MONITOR` for this purpose.
5
If the data being transferred is very large, consider using Oracle's built-in data transfer mechanisms like Data Pump (`expdp`/`impdp`) if applicable, as they are highly optimized for large datasets.