How long has the user been idle

          SELECT s.sid, s.username, q.odb_dbname database,
          dbinfo('UTC_TO_DATETIME',s.connected) conection_time,
          dbinfo('UTC_TO_DATETIME',t.run_time) last_run_time,
          current - dbinfo('UTC_TO_DATETIME',t.run_time) idle_time
          FROM syssessions s, systcblst t,  sysrstcb r, sysopendb q
          WHERE t.tid = r.tid AND s.sid = r.sid AND s.sid = q.odb_sessionid
          ORDER BY 6 DESC;

How to link a session to a transaction

  select tx_id
     from systrans 
     where tx_addr =  select us_txp 
          from sysuserthreads 
          where us_sid = SESSIONID);

How to find the busy tables

  select systabnames.tabname,
          sysptntab.pf_isread,
          sysptntab.pf_iswrite,
          sysptntab.pf_isrwrite,
          sysptntab.pf_isdelete,
          sysptntab.pf_seqscans 
          from systabnames, sysptntab 
          where systabnames.partnum = sysptntab.partnum;

How long has the database engine been running
 
          select dbinfo('UTC_TO_DATETIME', sh_curtime)
          - dbinfo('UTC_TO_DATETIME', sh_boottime)
          from sysshmvals;

How to find the current SQL statement

  select sqs_statement 
          from syssqlstat
          where sqs_statement;
          or
          select sqx_sessionid,
          sqx_conbno,
          sqx_sqlstatement
          from syssqexplain,
          sysscblst 
          where sqx_sessionid = sid 
          order by 1,2 ;