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merge join cartesian- access path?

From: Tlcbus <tlcbus_at_aol.com>
Date: 1997/10/29
Message-ID: <19971029025101.VAA17734@ladder02.news.aol.com>#1/1

To all: In order to improve performance, I created a small temp table from  original
big table to reduce joining operations. In step 4.2 I found merge join  cartesian step,
and my query never finishes. generally, cartesian join is caused by missing  joining
columns from 2 tables(This is not the case here). Any clues ?

thanks in advance Ted chyn

++++++++++++++++++++++++++++++++++++++++++++++
plan after creation of small temp work table

1.5331 SELECT STATEMENT Cost = 5331

   2.1 SORT GROUP BY

     3.1 HASH JOIN
       4.1 TABLE ACCESS FULL TEMP_WOSN_HEADER
       4.2 MERGE JOIN CARTESIAN =====What is this means ?
         5.1 VIEW
           6.1 SORT AGGREGATE
             7.1 TABLE ACCESS BY ROWID T_UTL_DATES
               8.1 INDEX UNIQUE SCAN I_PK_UDAT_CALENDAR_DY UNIQUE
         5.2 TABLE ACCESS BY ROWID T_WOSN_OPEN
            6.1 INDEX RANGE SCAN I_WSNO_UCD_DY NON-UNIQUE  
==================================================
original query - use nest loop join
1. SELECT STATEMENT Cost =

    2.1 SORT GROUP BY

     3.1 NESTED LOOPS
       4.1 NESTED LOOPS
         5.1 VIEW
           6.1 SORT AGGREGATE
             7.1 TABLE ACCESS BY ROWID T_UTL_DATES
               8.1 INDEX UNIQUE SCAN I_PK_UDAT_CALENDAR_DY UNIQUE
         5.2 TABLE ACCESS BY ROWID T_WOSN_OPEN
           6.1 INDEX RANGE SCAN I_WSNO_UCD_DY NON-UNIQUE
       4.2 TABLE ACCESS BY ROWID T_WOSN_HEADER
         5.1 INDEX RANGE SCAN I_WSNH_WOSN_CD NON-UNIQUE
       
Received on Wed Oct 29 1997 - 00:00:00 CST

Original text of this message

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