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IBM AIX 6.1 & Newer: TCP Connections Intermittently Failing ORA-12547 , TNS-12547, TNS-12560 and OS Error 32 (Doc ID 1084443.1)

Last updated on JUNE 16, 2022

Applies to:

Oracle Net Services - Version to [Release 10.2 to 18.1]
IBM AIX on POWER Systems (64-bit)


Connections to the database via the listener (i.e. TCP)  are limited in number and testing reveals that this number is fairly consistent.  A shutdown of database and listener will resolve the issue until  <n> number of TCP connections is established again.  Local or bequeath connections are NOT exhibiting this problem so local connections to the database are not failing at the time that this issue is reproducible.

In our example case, when the number of TCP connections exceeded 500, remote connections started to fail.  SQL*Plus connections using TCP failed with ORA-12547 and Tnspings that are launched remotely or on the server are failing with the following error:

 The failure to connect would be intermittent because as sockets are freed on the client,  newly spawned connections would be successful. 


This is a new installation of IBM AIX 6.1 or the operating system has recently been upgraded to version 6.1.  Alternatively, the Traffic regulation policy may have been configured or modified recently.


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