Troubleshooting
Problem
This article describes a possible resolution for connectivity problems by tuning the "Listen Queue depth" network configuration parameter.
Resolving The Problem
PROBLEM
You experience dropped connections and listener thread errors -25573 and oserr = 233, or "Network driver cannot accept a connection on the port". Another error frequently reported is listener-thread: err = -25580: oserr = 0: errstr = : System error occurred in network function.
SCOPE
This document applies to systems that implement the TCP/IP Internet protocol for database connectivity.
CAUSE
These errors can be an indication of a low configuration setting for the TCP "listen queue".
Important: This is only one possible cause of the problem. If this document does not provide you with a solution to your problem, you should search for other documents that refer to this topic.
SOLUTION
The operating system configuration parameter to set for the listen queue is platform dependent.
Example:
Solaris : tcp_conn_req_max_q
HP : tcp_conn_request_max
Steps to check and change the listen queue settings:
1. Confirm that the connections are being dropped. Run the command:
- netstat -s
Look for any connections requests dropped due to full queue.
2. If the number of connections dropped is greater than 0, use the ndd command to check the current settings.
Example:
- Solaris : ndd –get /dev/tcp tcp_conn_req_max_q
HP : ndd -get /dev/tcp tcp_conn_request_max
3. Use the ndd command with the -set option to adjust the operating system listen queue.
Example:
- To set the listen queue size to 256
Solaris : ndd -set /dev/tcp tcp_conn_req_max_q 256
HP : ndd -set /dev/tcp tcp_conn_request_max 256
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Document Information
Modified date:
16 June 2018
UID
swg21207733