Skewed Data or What?

From: jsfromynr <jatinder.1975_at_gmail.com>
Date: 27 Apr 2006 03:15:35 -0700
Message-ID: <1146132935.435480.80230@u72g2000cwu.googlegroups.com>

Hello All,
I am running this statement and got not get what this output means . At each step in the plan the cardinality is not what is actually returned.

for example at Step 0 Card = 412
but rows returned = 2598507

Is there something wrong ??
Is histrogram missing ??
When using ordered does the position of predicate and join conditions matter?? Do the position of tables matter while using ORDERED ?

SELECT /*+ Ordered */
b.gl_cd,
party_cd
FROM BR.ACCOUNT c ,BR.VOUCHER_DTL b
WHERE party_type = '6'
AND b.gl_cd LIKE '0807%'
AND b.gl_cd = c.gl_cd ;

Execution Plan

---

• 0 SELECT STATEMENT Optimizer=CHOOSE (Cost=399 Card=412 Bytes=8652) 1 0 TABLE ACCESS (BY INDEX ROWID) OF 'VOUCHER_DTL' (Cost=396 C ard=412 Bytes=4944) 2 1 NESTED LOOPS (Cost=399 Card=412 Bytes=8652) 3 2 TABLE ACCESS (BY INDEX ROWID) OF 'ACCOUNT' (Cost=3 Car d=1 Bytes=9) 4 3 INDEX (RANGE SCAN) OF 'ID_ACCOUNT_1' (NON-UNIQUE) (C ost=2 Card=34) 5 2 INDEX (RANGE SCAN) OF 'ID_VOUCHER_DTL_GL_CD' (NON-UNIQ UE) (Cost=387 Card=412)

Statistics

---

          0  recursive calls
          0  db block gets
     798541  consistent gets
     427805  physical reads
          0  redo size

   62771675 bytes sent via SQL*Net to client     6409868 bytes received via SQL*Net from client

     173235  SQL*Net roundtrips to/from client
          0  sorts (memory)
          0  sorts (disk)

***** 2598507 rows processed

Would it matter if I had written the statement like this using derived table?
SELECT /*+ Ordered */
b.gl_cd,
party_cd
FROM (select * from BR.ACCOUNT where party_type='6') c ,(select * from BR.VOUCHER_DTL where gl_cd like '0807%') b WHERE
--party_type = '6'
--AND b.gl_cd LIKE '0807%'
--AND

b.gl_cd = c.gl_cd ;

With Warm regards
Jatinder Singh Received on Thu Apr 27 2006 - 05:15:35 CDT