How to Trace SPID in Oracle SQL

1. Identified the process id if it present in alert log from any error or trace it from your self from SQL query with v$process view.

--- From alert log
WARNING: too many parse errors, count=1178 SQL hash=0xb94e2a38
PARSE ERROR: ospid=2776, error=918 for statement:
2018-12-03T16:59:31.252004-06:00 

--From SQL Query trace yourself
select p.PID,p.SPID,s.SID from v$process p,v$session s
where s.paddr = p.addr and s.sid = &SESSION_ID;

2. Login sqlplus as sysdba and start the trace process

sqlplus / as sysdba
oradebug setospid XXXX;   -- XXXX is process id
oradebug unlimit;
oradebug tracefile_name;
oradebug event 10046 trace name context forever,level 12; 

Example:
sqlplus / as sysdba
oradebug setospid 2776;
oradebug unlimit;
oradebug tracefile_name;
oradebug event 10046 trace name context forever,level 12;

3. Wait for the issue to be reproduced.

Wait for error to occurred again.

4. Disable the trace process.

oradebug event 10046 trace name context off;
exit