One thing I've noticed is the extreme amount of time that Oracle RAW data types take when DBD::Oracle thinks they are strings. You might consider binding your ACCT_SESSION_ID listed in the code if that value is a RAW using something like the following:

$sth->bind_param(0, pack('H*', '0B00FFFF90000010-40647961'), { ora_type => ORA_RAW });

This will save you lots of churning on the database side, as ORACLE will need to convert it to a raw value if you don't specify. We noticed a substantial performance difference when doing this with all of our RAW columns. Also as noted by others, { Autocommit => 0 } will be a big difference in speed.