Distributed Transaction Fails using database link

Symptoms: When having a transaction with database link involved, it results in an error that says:
ORA-03150: end-of-file on communication channel for database link
ORA-02055: distributed update operation failed; rollback required
ORA-02063: preceding lines from DBLINK_NAME.

Perhaps you already have checked the database link if its working and no problem, it returns data, but on your procedure or package dont.

Cause: This is a bug that happens on Oracle 11.2.0.4 and later.
It is reported with more details on the Doc ID:
(Doc ID 1909692.1) Distributed Transaction Fails with ORA-03150 ORA-02055, alert log shows ORA-07445: [qsmmixGetIdxKeyStats()+231]

Solution: As it is mentioned on the Oracle Support, there is a patch that fixes the bug.
Apply that using the instructions given with the patch.

- For Non-RAC Environments (Standalone Databases): 
$ opatch apply online -connectString <SID>:<USERNAME>:<PASSWORD>:
- For RAC Environments:
$ opatch apply online -connectString <SID_Node1>:<Username_Node1>:<Password_Node1>:<Node1_Name>,<SID_Node2>:<Username_Node2>:<Password_Node2>:<Node2_Name>,<SID_NodeN>:<Username_NodeN>:<Password_NodeN>:<NodeN_Name>

Error on ftp service OOPS: cannot locate user entry:nobody.

Symptoms: When trying to access the Linux ftp service it gives an error on client side, such as:
OOPS: cannot locate user entry:nobody.

Cause: By default, the vsftp service looks for this user even though there is no anonymous connection.
The message error is similar to this:
OOPS: cannot locate user entry:nobody.

Solution: Make sure it exists the Linux user called nobody.
Otherwise, create it, restart the ftp service and try again.

Starting TNS Listener or LSNRCTL TNS-12541, Linux Error: 111: Connection Refused

Symptoms:  Starting TNS Listener or LSNRCTL TNS-12541, Linux Error: 111: Connection Refused


Cause: You try to start the Oracle Listener and gets the error such as this:

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC)))
TNS-12541: TNS:no listener
 TNS-12560: TNS:protocol adapter error
  TNS-00511: No listener
   Linux Error: 111: Connection refused


There is possibly an incorrect IP Address specified for the host in the /etc/hosts file.
Also, the localhost reference may be incorrect or missing from the /etc/hosts file.
Oracle may not have read access to /etc/nsswitch.conf file.


Solution: Correct or make sure the mapping in the /etc/hosts file is ok (ex: 192.168.1.10     dbserver1.domain.com     dbserver).

Check that the localhost loopback name and address are correct (both long and short host names).
Ex:
127.0.0.1     localhost.localdomain    localhost

Check permissions on /etc/nsswitch.conf file to ensure group and other have read access.
If necessary change permisions on /etc/nsswitch.conf as follows:
chmod 644 /etc/nsswitch.conf


keywords:  TNS-12560, TNS-12537, TNS-00507, lsnrctl,
Doc ID 343295.1