Sometimes You can get “ORA-12615: TNS:preempt error ” error.
Details of error are as follows.
ORA-12615: TNS:preempt error
This error is related with the Too many concurrent connection requests.
Increase the queuesize as follows.
LISTENER = (DESCRIPTION_LIST = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.63.34)(PORT = 1521)(QUEUESIZE=1000)) (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521)) ) )
Each new shadow process that is spawned tries to create the ADR directories, even if they already exist.
This is due to Unpublished Bug:9700115 CHECK ADR DIRECTORIES EXISTENCE AND ATTRIBUTES FIRST BEFORE CREATING THEM
Apply Patch:9700115 to change the behavior of the ADR to check if the subdirectories exists before it tries to create them.
Do you want to learn more details about RMAN, then read the following articles.