Truncate table related questions

Question

Hi Folks,
Environment: 10g Rel 2
I am trying to prove the following two points by way of experimentation
a, The truncate table operation will reset the high water mark (HWM) to the first usable data block in the table segment
# Take a HWM snap shot before the truncate operation
select a.BLOCKS - b.EMPTY_BLOCKS -1 HWM
from
  (SELECT BLOCKS
   FROM   DBA_SEGMENTS
   WHERE  OWNER=UPPER('JIM') AND SEGMENT_NAME = UPPER('EMPLOYEES')) a,
   (SELECT EMPTY_BLOCKS
    FROM   DBA_TABLES
    WHERE  OWNER=UPPER('JIM') AND TABLE_NAME = UPPER('EMPLOYEES')) b;Output: 7
truncate table JIM.EMPLOYEES;
Re ran the above code and got the same result (i.e. 7 blocks). I was expecting to see 0 blocks instead? Is the above query the right method of
finding the HWM?
b, The truncate operation will also truncate the corresponding indexes for the table
Q, Is there a view that will show all the index values of the table? These values will probably be meaningless, but I would like to see them before
and after the truncate operation.
Thanks
rogers42

Answer 1

a) If you would have read on the empty_blocks column in dba_tables, you would have known it is populated by dbms_stats.
Did you run dbms_stats.analyze_table?
b)
There is no such view.
All dictionary views are documented in the view DICT and the online documentation.
Sybrand Bakker