[8i] Can someone help me on using explain plan, tkprof, etc.?

Question

I am trying to follow the instructions at When your query takes too long ...
I am trying to figure out why a simple query takes so long.
The query is:
SELECT COUNT(*) AS tot_rows FROM my_table;It takes a good 5 minutes or so to run (best case), and the result is around 22 million (total rows).
My generic username does not (evidently) allow access to PLAN_TABLE, so I had to log on as SYSTEM to run explain plan. In SQL*Plus, I typed in:
explain plan for (SELECT COUNT(*) AS tot_rows FROM my_table);and the response was "Explained."
Isn't this supposed to give me some sort of output, or am I missing something?
Then, the next step in the post I linked is to use tkprof. I see that it says it will output a file to a path specified in a parameter. The only problem is, I don't have access to the db's server. I am working remotely, and do not have any way to remotely (or directly) access the db server. Is there any way to have the file output to my local machine, or am I just S.O.L.?

Answer 1

SomeoneElse used "create table as" (CTAS), wich automatically gathers the stats. You can see the differende before and after stats clearly in this example.
This is the script:
drop table ttemp;
create table ttemp (object_id number not null, owner varchar2(30), object_name varchar2(200));
alter table ttemp add constraint ttemp_pk primary key (object_id);
insert into ttemp
select object_id, owner, object_name
from dba_objects
where object_id is not null;
set autotrace on
select count(*) from ttemp;
exec dbms_stats.gather_table_stats('PROD','TTEMP');
select count(*) from ttemp;And the result:
Table dropped.
Table created.
Table altered.
46888 rows created.
  COUNT(*)
     46888
1 row selected.
Execution Plan
           SELECT STATEMENT Optimizer Mode=CHOOSE
   1         SORT AGGREGATE
   2    1      TABLE ACCESS FULL PROD.TTEMP
Statistics
          1  recursive calls
          1  db block gets
        252  consistent gets
          0  physical reads
        120  redo size
          0  PX remote messages sent
          0  PX remote messages recv'd
          0  buffer is pinned count
          0  workarea memory allocated
          4  workarea executions - optimal
          1  rows processed
PL/SQL procedure successfully completed.
  COUNT(*)
     46888
1 row selected.
Execution Plan
           SELECT STATEMENT Optimizer Mode=CHOOSE (Cost=4 Card=1)
   1         SORT AGGREGATE (Card=1)
   2    1      INDEX FAST FULL SCAN PROD.TTEMP_PK (Cost=4 Card=46 K)
Statistics
          1  recursive calls
          2  db block gets
        328  consistent gets
          0  physical reads
       8856  redo size
          0  PX remote messages sent
          0  PX remote messages recv'd
          0  buffer is pinned count
          0  workarea memory allocated
          4  workarea executions - optimal
          1  rows processed