My Oracle Support Banner

Connections to Database Fail Reporting ORA-12547: TNS lost connection (Doc ID 1289174.1)

Last updated on JANUARY 28, 2011

Applies to:

Oracle Net Services - Version: 9.2.0.8 and later   [Release: 9.2 and later ]
Information in this document applies to any platform.

Symptoms

Connections to the database, intermittently start to fail, reporting the error code ORA-12547: TNS lost connection.Upon checking the server, Netstat command shows many threads with a state of LISTENING  for local and Foreign address 0.0.0.0

Proto Local Address Foreign Address State     PID

TCP   0.0.0.0:53    0.0.0.0:0       LISTENING 1564
TCP   0.0.0.0:88    0.0.0.0:0       LISTENING 408
TCP   0.0.0.0:135   0.0.0.0:0       LISTENING 740
TCP   0.0.0.0:389   0.0.0.0:0       LISTENING 408
TCP   0.0.0.0:445   0.0.0.0:0       LISTENING 4
TCP   0.0.0.0:464   0.0.0.0:0       LISTENING 408
TCP   0.0.0.0:593   0.0.0.0:0       LISTENING 740
TCP   0.0.0.0:636   0.0.0.0:0       LISTENING 408
TCP   0.0.0.0:1030  0.0.0.0:0       LISTENING 408
TCP   0.0.0.0:1031  0.0.0.0:0       LISTENING 408
TCP   0.0.0.0:1044  0.0.0.0:0       LISTENING 1772
TCP   0.0.0.0:1114  0.0.0.0:0       LISTENING 2000
TCP   0.0.0.0:1117  0.0.0.0:0       LISTENING 3656
TCP   0.0.0.0:1139  0.0.0.0:0       LISTENING 3236
TCP   0.0.0.0:1263  0.0.0.0:0       LISTENING 1564
TCP   0.0.0.0:1581  0.0.0.0:0       LISTENING 2000
TCP   0.0.0.0:3268  0.0.0.0:0       LISTENING 408
TCP   0.0.0.0:3269  0.0.0.0:0       LISTENING 408
TCP   0.0.0.0:3389  0.0.0.0:0       LISTENING 3000
TCP   0.0.0.0:4899  0.0.0.0:0       LISTENING 1896
TCP   0.0.0.0:17970 0.0.0.0:0       LISTENING 19

Oracle Net level 16 server tracing of the processes, shows connections are not completing,
Summary of key sections of trace, all 12k in size
[10-12-2010 11:31:33:026] niotns: Not enabling dead connection detection.
[10-12-2010 11:31:33:026] niotns: listener bequeathed shadow coming to life...

[10-12-2010 11:31:33:026] nsinherit: doing connect handshake..

[10-12-2010 11:31:33:026] nsinherit: ADR="(ADDRESS=(PROTOCOL=tcp)(DEV=340)(HOST=xxx.xxx.xx.xx)(PORT=1521))"
[10-12-2010 11:31:33:026] ntprd: entry
[10-12-2010 11:31:33:026] sntpread: entry
[10-12-2010 11:31:33:026] sntpread: Attempting to read 4 bytes from 24796

[10-12-2010 11:31:33:026] nttgetport: port resolved to 1521
[10-12-2010 11:31:33:026] nttgetport: exit
[10-12-2010 11:31:33:026] nttbnd2addr: using host IP address: xxx.xxx.xx.xx

All the traces end here

[10-12-2010 11:31:33:042] nsopen: opening transport...
[10-12-2010 11:31:33:042] nttcon: entry
[10-12-2010 11:31:33:042] nttcon: toc = 3
[10-12-2010 11:31:33:042] nttcnp: entry
[10-12-2010 11:31:33:042] nttcnp: getting sockname
[10-12-2010 11:31:33:042] nttcnp: exit
[10-12-2010 11:31:33:042] nttcnr: entry
[10-12-2010 11:31:33:042] nttcnr: waiting to accept a connection.

Sockets are never released and a restart of the database free the resources.
ORA-12547 is a sympton of lack of sockets on the system
Setting SQLNET.EXPIRE_TIME does not help

Cause

To view full details, sign in with your My Oracle Support account.

Don't have a My Oracle Support account? Click to get started!


In this Document
  Symptoms
  Cause
  Solution

This document is being delivered to you via Oracle Support's Rapid Visibility (RaV) process and therefore has not been subject to an independent technical review.

My Oracle Support provides customers with access to over a million knowledge articles and a vibrant support community of peers and Oracle experts.