High query IO wait

Question

I have a query that take huge amount of IO waits:
table address (ENT_ID, ADDR1, ADDR2,CITY, STATE, zip, COUNTRY, ADDR_ID, ACCT_ID, VALID_FROM_DT, VALID_THRU_DT, STAT, addr_hash, sys_delete_dt, mhh,ADDR_TYPE)
single reversed indexes on ADDR_HASH, acct_id, addr_id
Composite PK on ENT_ID, ADDR_TYPE, ACCT_ID, STAT
here is the query:
SELECT ENTITY_ID, ADDR1, CITY, STATE, zip, COUNTRY, ADDR_ID, ACCT_ID, VALID_FROM_DT, VALID_THRU_DT FROM ADDRESS WHERE ADDR_HASH = :1 AND SYS_DELETE_DT IS NULL;
The query uses the right index on addr_hash to obtain TABLE ACCESS BY INDEX ROWID over the index range scan.
Please advise what can I do to optimize this query?
Thanks a lot,mj

Answer 1

Yes, it was analyzed earlier yesterday immediatelly before the processes start hitting the DB. - 10.1.0.4/aix 5.3
I do not see anything wrong with the execution to require so long IO waits.... Please, let me know what I did oversee...
The IO wait time is measured by the query:
select distinct sql_text, sql_id, elapsed_time, cpu_time, user_io_wait_time
from sys.v_$sqlarea
order by 5 desc;
Execution Plan
0 SELECT STATEMENT Optimizer=FIRST_ROWS (Cost=1 Card=1 Bytes=3
23)
1 0 TABLE ACCESS (BY INDEX ROWID) OF 'ADDRESS' (TABLE) (Cost=1
Card=1 Bytes=323)
2 1 INDEX (RANGE SCAN) OF 'IX_ADDR_HASH' (INDEX) (Cost=1 Car
d=1)
Statistics
1 recursive calls
0 db block gets
4 consistent gets
1 physical reads
0 redo size
449 bytes sent via SQL*Net to client
235 bytes received via SQL*Net from client
1 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
0 rows processed
Thanks a lot,mj