One of my users is running following query to update.

HTML Code:
update BM_ANUSALES_OCT2005 bm set totalmou=
(select sum(rated_volume)/60 from tnpostpaid.rtx_jul_aug 
where r_p_contract_id=bm.co_id and 
r_p_customer_id=bm.customer_id and
rtx_ent_date>=bm.act_date and 
rtx_ent_date<=bm.end_date and 
sncode=1 and call_type=1 and xfile_ind='H') 
where act_date < '01-Aug-2005'
he said its running very slow so i traced his session and found that trace file contains ony foll nothing else...


HTML Code:
Redo thread mounted by this instance: 1
Oracle process number: 24
Unix process pid: 19270, image: oracle@cbemis (TNS V1-V3)

*** 2005-10-07 11:00:39.230
*** SESSION ID:(38.46742) 2005-10-07 11:00:39.173
WAIT #1: nam='db file sequential read' ela= 22 p1=90 p2=110268 p3=1
WAIT #1: nam='db file sequential read' ela= 26 p1=90 p2=71954 p3=1
WAIT #1: nam='db file sequential read' ela= 157 p1=90 p2=71955 p3=1
WAIT #1: nam='db file sequential read' ela= 13 p1=90 p2=71956 p3=1
WAIT #1: nam='db file sequential read' ela= 14 p1=90 p2=71957 p3=1
WAIT #1: nam='db file sequential read' ela= 13 p1=90 p2=71958 p3=1
WAIT #1: nam='db file sequential read' ela= 13 p1=90 p2=71959 p3=1
WAIT #1: nam='db file sequential read' ela= 14 p1=90 p2=71960 p3=1
WAIT #1: nam='db file sequential read' ela= 13 p1=90 p2=71961 p3=1
WAIT #1: nam='db file sequential read' ela= 12 p1=90 p2=71962 p3=1
WAIT #1: nam='db file sequential read' ela= 17 p1=90 p2=110269 p3=1
WAIT #1: nam='db file sequential read' ela= 18 p1=90 p2=71963 p3=1
WAIT #1: nam='db file sequential read' ela= 139 p1=90 p2=71964 p3=1
WAIT #1: nam='db file sequential read' ela= 12 p1=90 p2=71965 p3=1
WAIT #1: nam='db file sequential read' ela= 13 p1=90 p2=71966 p3=1
WAIT #1: nam='db file sequential read' ela= 18 p1=90 p2=71967 p3=1
WAIT #1: nam='db file sequential read' ela= 14 p1=90 p2=71968 p3=1
WAIT #1: nam='db file sequential read' ela= 13 p1=90 p2=71969 p3=1
WAIT #1: nam='db file sequential read' ela= 12 p1=90 p2=71970 p3=1
WAIT #1: nam='db file sequential read' ela= 17 p1=90 p2=110270 p3=1
WAIT #1: nam='db file sequential read' ela= 15 p1=90 p2=71971 p3=1
and it looks like session is waiting for indefinite time...
what need s to be done. From asktom i got to know that it is bcoz of sinle block read index scans but i am not sure what to do.

Oracle 9.2.0.6.0
HP-UX-11i
Any thoughts....

Rgds
Parag