ORA-16957: SQL Analyze time limit interrupt
The ORA-16957 error is an internal error code used to indicate that SQL analyze has reached its time limit.
According to MOS Doc ID 1275248.1 ,
(This is an unpublished bug. The bug is fixes in version 12.1)
The error ORA-16957: SQL Analyze time limit interrupt, can be ignored safely, as it does not indicate any problems with the database.
If the error ORA-16957: SQL Analyze time limit interrupt comes along with
ORA-00600: internal error code, arguments: , , , , , , , 
you cannot simply ignore it, you have to read the below MOS note and apply recommended patches:
ORA-600 And ORA-16957 Reported While Running DBMS_SCHEDULER (Doc ID 743873.1)