Why is query taking too much time ?

Question

Hi gurus,
I have a table name test which has 100000 records in it,now the question i like to ask is.
when i query select * from test ; no proble with responce time, but when the next day i fire the above query it is taking too much of time say 3 times.i would also like to tell you that everything is ok in respect of tuning,the db is properly tuned, network is tuned properly. what could be the hurting factor here ??
take care
All expertise.

Answer 1

Here is a small test on my windows PC.
oracle 9i Rel1.
Table : emp_test
number of records : 42k
set autot trace exp stat
15:29:13 jaffar@PRIMEDB> select * from emp_test;
41665 rows selected.
Elapsed: 00:00:02.06 ==> response time.
Execution Plan
0 SELECT STATEMENT Optimizer=CHOOSE (Cost=24 Card=41665 Bytes=916630)
1 0 TABLE ACCESS (FULL) OF 'EMP_TEST' (Cost=24 Card=41665 Bytes=916630)
Statistics
0 recursive calls
0 db block gets
2951 consistent gets
178 physical reads
0 redo size
1268062 bytes sent via SQL*Net to client
31050 bytes received via SQL*Net from client
2779 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
41665 rows processed
15:29:40 jaffar@PRIMEDB> delete from emp_test where deptno = 10;
24998 rows deleted.
Elapsed: 00:00:10.06
15:31:19 jaffar@PRIMEDB> select * from emp_test;
16667 rows selected.
Elapsed: 00:00:00.09 ==> response time
Execution Plan
0 SELECT STATEMENT Optimizer=CHOOSE (Cost=24 Card=41665 Bytes=916630)
1 0 TABLE ACCESS (FULL) OF 'EMP_TEST' (Cost=24 Card=41665 Bytes=916630)
Statistics
0 recursive calls
0 db block gets
1289 consistent gets
0 physical reads
0 redo size
218615 bytes sent via SQL*Net to client
12724 bytes received via SQL*Net from client
1113 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
16667 rows processed