The database connection times out with Oracle errors.
Symptoms
The database connection times out with the following errors,
which occur when the Oracle listener backlog is full:
ORA-12535
TNS: Operation timed out error
ORA-12541 No
listener error
Causes
The Oracle QUEUESIZE parameter value in the listener.ora
file does not specify enough connections for the listener to handle
large volumes of concurrent connection requests.
Resolving the problem
Change the number of connections defined by the QUEUESIZE
parameter. To set the QUEUESIZE parameter, edit the address line in
the listener.ora file, as follows:
(ADDRESS = (PROTOCOL = TCP)(HOST = servername)(PORT
= portnumber)(QUEUESIZE=number))For
more information, see the Handling Large Volumes of Concurrent
Connection Requests article (in the Oracle Database Net
Services Administrator's Guide) at the Oracle documentation
website for the version of Oracle Database that
you are using.