Query Execution Plan showing high cost

 Hi,

My query is taking 16 seconds time in one database and the same query is taking less than 1 sec in another database.

When I see explain auto trace, I see high cost value. Where can I tune this? Database version : 9.2.0.8

Query:   SELECT report_date, rep_type, account_type, doc_update_type, issue_type,
              event_type_flag, interim_type
  FROM comp_section_signoff_detls_log a
 WHERE a.PPI = 'C036F4590' and a.SECTION_CODE = '02'
   AND a.log_status = 'P'
   AND a.log_id IN (
          SELECT MAX (log_id)
            FROM comp_section_signoff_detls_log b
           WHERE b.ppi = a.ppi