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Oracle: DBMS_SYSTEM.SET_SQL_TRACE_IN_SESSION

set_sql_trace_in_session is just a convenience function to set diagnostic event 10046 (with level 1) in a session.
Using dbms_system.set_sql_trace_in_session, it is possible to enable tracing of SQL statement execution in other session.
For the own session, one might consider using 
alter session set sql_trace=true;
Trace SQL execution in the entire instance: 
alter system set sql_trace=true;

See also

dbms_system.set_ev, dbms_support.start_trace.
SQL tracing is required to use tkprof.

Index

Fatal error: Uncaught PDOException: SQLSTATE[HY000]: General error: 8 attempt to write a readonly database in /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php:78 Stack trace: #0 /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php(78): PDOStatement->execute(Array) #1 /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php(30): insert_webrequest_('/notes/developm...', 1758207258, '216.73.216.150', 'Mozilla/5.0 App...', NULL) #2 /home/httpd/vhosts/renenyffenegger.ch/httpsdocs/notes/development/databases/Oracle/installed/packages/dbms/system/api/set_sql_trace_in_session(50): insert_webrequest() #3 {main} thrown in /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php on line 78