As usual Wolfgang you are right. I didnt know you have to multiply the 30 * 6 million.... Thanks Alex On 1/30/07, Wolfgang Breitling <breitliw@xxxxxxxxxxxxx> wrote:
At 09:08 AM 1/30/2007, amonte wrote: >This is puzzling me > >a change from NL to HASH (by using USE_HASH) then plan changed which >is obvious but also the stats? TUH_NVPAGINA which has over 2000 >million of rows now shows correct estimation under HASH but showed a >miserable 6 million using NL. What is causing this? In the NL plan there is a flter predicate on TUH_NVPAGINA. It will read TUH_NVPAGINA an estimated 30 times (rows from step 3) returning ~6M rows each time for an estimated 30*6M = 180M rows coming out of the nested loop (step 2 rows = 182M) In the HA plan it reads TUH_NVPAGINA once, all 2163M rows (there is no a access or filter predicate for step 5). Those 2163M rows are than hashed in step 2 against the 30 rows out of step3 returning the same estimated 182M rows. >-------------------------------------------------------------------------------------------- >| Id | Operation | Name | Rows | Bytes | >Cost | Pstart| Pstop | >-------------------------------------------------------------------------------------------- > >| 0 | SELECT STATEMENT | | 934 | 49502 >| 1022K| | | >| 1 | SORT GROUP BY | | 934 | 49502 >| 1022K| | | >| 2 | NESTED >LOOPS | | 182M| 9213M| 814K| | | >|* 3 | TABLE ACCESS FULL | TUD_FEDIA | 30 | 480 >| 3 | | | >| 4 | PARTITION RANGE >ITERATOR| | | | | KEY | KEY | >|* 5 | TABLE ACCESS FULL | TUH_NVPAGINA | 5992K| 211M| >27159 | KEY | KEY | >-------------------------------------------------------------------------------------------- > >Predicate Information (identified by operation id): >--------------------------------------------------- > > 3 - filter("TUD_FEDIA"."ID_MES"=TO_NUMBER(:Z)) > 5 - filter("TUH_NVPAGINA"."FE_DIA"="TUD_FEDIA"."FE_DIA") > >-------------------------------------------------------------------------------------------- >| Id | Operation | Name | Rows | Bytes | >Cost | Pstart| Pstop | >-------------------------------------------------------------------------------------------- > >| 0 | SELECT STATEMENT | | 934 | 49502 >| 1555K| | | >| 1 | SORT GROUP BY | | 934 | 49502 >| 1555K| | | >|* 2 | HASH >JOIN | | 182M| 9213M| 1347K| | | >|* 3 | TABLE ACCESS FULL | TUD_FEDIA | 30 | 480 >| 3 | | | >| 4 | PARTITION RANGE >ITERATOR| | | | | KEY | KEY | >| 5 | TABLE ACCESS FULL | >TUH_NVPAGINA | 2163M| 74G| 1330K| KEY | KEY | >-------------------------------------------------------------------------------------------- > >Predicate Information (identified by operation id): >--------------------------------------------------- > > 2 - access("TUH_NVPAGINA"."FE_DIA"="TUD_FEDIA"."FE_DIA") > 3 - filter("TUD_FEDIA"."ID_MES"=TO_NUMBER(:Z)) Regards Wolfgang Breitling Centrex Consulting Corporation www.centrexcc.com ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________ -- //www.freelists.org/webpage/oracle-l