To answer this questions :
To give you useful information over time :
Just choose the level of audit (every page view in the website or an insert into a table) and install :
Take in memory that the built-in auditing will go always faster than the custom one.
After making sure AUDIT_TRAIL was set in the ini.ora parameter file.
create table t1 ( x int );
audit insert on t1 by access;
create table t2 ( x int );
create table t2_audit
as
select sysdate dt, a.*
from v$session a
where 1=0;
create index t2_audit_idx on t2_audit(sid,serial#);
create trigger t2_audit
after insert on t2
begin
insert into t2_audit
select sysdate, a.*
from v$session a
where sid = ( select sid from V$mystat where rownum = 1 );
end;
/