Error oracle- ORA-00018: maximum number of sessions exceeded

ORA-00018:  maximum number of sessions exceeded

Cause:     All session state objects are in use.

Action:     Increase the value of the SESSIONS initialization parameter.

Error oracle- ORA-00017: session requested to set trace event

ORA-00017:  session requested to set trace event

Cause:     The current session was requested to set a trace event by another session.

Action:     This is used internally; no action is required.

Error oracle- ORA-00001: unique constraint (string.string) violated

ORA-00001:  unique constraint (string.string) violated

Cause:     An UPDATE or INSERT statement attempted to insert a duplicate key. For Trusted Oracle configured in DBMS MAC mode, you may see this message if a duplicate entry exists at a different level.

Action:     Either remove the unique restriction or do not insert the key.