Re: Explain: In List Iterator

There are two odd features I would pursue:

There is no join to the customer table and that is why (I guess) you have a cartesian merge join between CUSTOMER and everything else.

The second thing is that despite the inlist iterator, Oracle thinks that the rest of the query will return approximately one row. So are the statistics out of date in a critical way - e.g. is the serieno that you list generate by a sequence and analyzed in such a way that your supplied values are all far out from the actual column values (check low and high in user_tab_columns).

The oddity about the plan is that the inlist iterator (which others have explained) is followed by Oracle doing:

        get rowids
        convert rowids to bitmap
        convert bitmap to rowids
        get rows by rowid.

Conversion usually happens so that something useful can happen between the two stages (such as bitmap AND, bitmap MERGE etc.)

Jonathan Lewis
http://www.jlcomp.demon.co.uk

Host to The Co-Operative Oracle Users' FAQ http://www.jlcomp.demon.co.uk/faq/ind_faq.html

Author of:
Practical Oracle 8i: Building Efficient Databases

-----Original Message-----
To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com> Date: 09 April 2002 21:20

|Hi, list.
|I'm trying to find out what's eating my system. I found the query,
and
|explain'ed it. I've never seen an "in list iterator" before. Can
anyone
|tell me what that is???
|
|Thanks!!
|
|Barb
|
|Execution Plan
|----------------------------------------------------------
| 0 SELECT STATEMENT Optimizer=CHOOSE (Cost=2398 Card=25814
|Bytes=9964204)
| 1 0 SORT (UNIQUE) (Cost=2398 Card=25814 Bytes=9964204)
| 2 1 MERGE JOIN (CARTESIAN) (Cost=969 Card=25814
Bytes=9964204)
| 3 2 NESTED LOOPS (OUTER) (Cost=1 Card=1 Bytes=380)
| 4 3 NESTED LOOPS (Cost=8 Card=1 Bytes=324)
| 5 4 INLIST ITERATOR (CONCATENATED)
| 6 5 TABLE ACCESS (BY INDEX ROWID) OF 'AD'
(Cost=1590
|Card=145 Bytes=20300)
| 7 6 BITMAP CONVERSION (TO ROWIDS)
| 8 7 BITMAP CONVERSION (FROM ROWIDS)
| 9 8 INDEX (RANGE SCAN) OF 'I_AD2'
(NON-UNIQUE)
| 10 4 TABLE ACCESS (BY INDEX ROWID) OF 'PUB' (Cost=1
Card=3600
|Bytes=662400)
| 11 10 INDEX (UNIQUE SCAN) OF 'I_PUB1' (UNIQUE)
| 12 3 TABLE ACCESS (BY INDEX ROWID) OF 'INVROWS' (Cost=1
|Card=627725 Bytes=35152600)
| 13 12 INDEX (RANGE SCAN) OF 'I_INVR1' (NON-UNIQUE)
(Cost =1
|Card=627725)
| 14 2 SORT (JOIN) (Cost=968 Card=25814 Bytes=154884)
| 15 14 TABLE ACCESS (FULL) OF 'CUSTOMER' (Cost=968
Card=25814
|Bytes=154884)
|
|
|
|
|SELECT DISTINCT a.serieno, p.paper, p.adno, p.pubno, p.class,
p.xsize,
|p.ysize,
|p.state, trunc(p.mdate) mdate, p.vno, a.unet, trunc(a.rdate) rdate,
|trunc(a.startdate) startdate, trunc(a.enddate) enddate, a.ratecode,
|a.cus4name,
|a.cus2no, i.dcode, i.ino FROM arcdb.ad a, arcdb.pub p, arcdb.invrows
i,
|advdb.customer c WHERE p.adno = a.adno AND p.vno = a.vno AND p.adno =
|i.adno(+)
|AND p.vno = i.vno(+) AND p.pubno = i.pubno(+) AND a.serieno IN
|(7,8,24,31,33,39,52,58,60,63,137,144,419,434,440,444,445,451,463) AND
|p.paper =
|'DNA' AND p.state IN ('NOT', 'VAR') AND p.adno > 0 AND p.pubno = 1
AND
|p.vnoflag
|= 'Y'AND c.cgrno = 'TT' AND trunc(a.rdate) BETWEEN
to_date('01-MAR-02',
|'DD-MON-YY') AND to_date('07-MAR-02', 'DD-MON-YY')
|
|--
|Please see the official ORACLE-L FAQ: http://www.orafaq.com
|--
|Author: Baker, Barbara
| INET: bbaker_at_denvernewspaperagency.com
|
|Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
|San Diego, California -- Public Internet access / Mailing
Lists
|--------------------------------------------------------------------
|To REMOVE yourself from this mailing list, send an E-Mail message
|to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
|the message BODY, include a line containing: UNSUB ORACLE-L
|(or the name of mailing list you want to be removed from). You may
|also send the HELP command for other information (like subscribing).

-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Jonathan Lewis
  INET: jonathan_at_jlcomp.demon.co.uk

Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051
San Diego, California        -- Public Internet access / Mailing Lists
--------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from).  You may
also send the HELP command for other information (like subscribing).