Locked User in EBS R12

Today one of users complaining about failed login. Using user administration I found that the user's status is 'LOCKED'. It was the first time I met this problem. The question was how to unlock the user?

After searching Oracle Support with no result, I opened the FND_USERS table and found that the value for ENCRYPTED_FOUNDATION_PASSWORD and ENCRYPTED_USER_PASSWORD for locked users are INVALID.

So I changed the password from the applications and then LOCKED status disappeared.

ORA-06512: at "SYS.DBMS_SNAPSHOT_UTL", line 960

When creating materialized view, do not query directly from database link.
Below query will be failed:

CREATE MATERIALIZED VIEW "ABC"
TABLESPACE "XYZ"
PCTFREE 10 MAXTRANS 255 STORAGE ( INITIAL 64K BUFFER_POOL DEFAULT)
NOLOGGINGPARALLEL (DEGREE 4) CACHE USING NO INDEX
REFRESH FORCE START WITH to_date('04-11-2011 11:58:35','MM-dd-yyyy hh24:mi:ss') NEXT sysdate + 1/24 AS select * from abc@dblink

You can create a view first and select from the view, or:

CREATE MATERIALIZED VIEW "ABC"
TABLESPACE "XYZ"
PCTFREE 10 MAXTRANS 255 STORAGE ( INITIAL 64K BUFFER_POOL DEFAULT)
NOLOGGINGPARALLEL (DEGREE 4) CACHE USING NO INDEX
REFRESH FORCE START WITH to_date('04-11-2011 11:58:35','MM-dd-yyyy hh24:mi:ss') NEXT sysdate + 1/24 AS select * from (select * from abc@dblink)

Rupam Verma' Blog: Negative Values For Tablespace

If you see some negative value on Enterprise Manager Grid Control 11g or on Database Console 11g while listing datafiles for a tablespace then this is your answer:

Rupam Verma' Blog: Negative Values For Tablespace: "9548105"