ORA-609 with TNS-12537: TNS:connection closed

          ORA-609 with TNS-12537: TNS:connection closed

We almost time receive an error such as ora-609 which shows in alert log as

TNS- TNS-12537: TNS:connection closed
        ns secondary err code: 12560
        nt main err code: 0
        nt secondary err code: 0
        nt OS err code: 0
    opiodr aborting process unknown ospid (12345) as a result of ORA-609

This error means could not attach to incoming connection, so our database process was aborted or closed because incoming connection was not passed to it by listener. In our case we found sqlnet error stack as shown below

 TNS-12537: TNS:connection closed

It means the dedicated process didn’t have a client connection anymore to work.

As we all know the process of client connections:

1. First Client initiates a connection to the database so it connects to the listener.

2. Then listener starts a dedicated DB process that will receive this connection or session.

3. After that, this dedicate process is started and listener passes the connection from the client to this process.

4. Then the sever process takes the connection from the listener to continue the handshake with the client.

5. After that Server process and client exchange messages or information required for establishing a session or user logon.

6. Then the session is opened now.

In our case, it may be when the dedicated process tries to communicate with the client it finds that connection was closed.

Solution or Work around:

We can eliminate this error by increasing the value of SQLNET.INBOUND_CONNECT_TIMEOUT in sqlnet.ora file. 

By default the SQLNET.INBOUND_CONNECT_TIMEOUT value is 60 seconds.

The sqlnet.ora file can be found in RDBMS_HOME/network/admin.

For example:

$ cd $ORACLE_HOME/network/admin

$vi sqlnet.ora

And change the value of SQLNET.INBOUND_CONNECT_TIMEOUT as:

SQLNET.INBOUND_CONNECT_TIMEOUT=300

Then save the file.

There are many more possibilities which can cause this error such as:

1. This can happen suppose our client closed the connection immediately after initiating it.

2. This may occur when firewall kill the connection.

3. Sometimes, it may happen because of Database, OS or network performance problem.

4. This error may occur when some client crashes.

Hope this may also useful here:

ORA-00313ORA-00312 ORA-27037

Create or Rebuild Context file in DB Tier

ORA-01092

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Oracle Apps

Oracle Database

Hope this may useful and helpful. Please let us know for any concerns either by below comments or write to @contact us: https://ora-data.blogspot.in/

Regards,
ora-data Team