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Home -> Community -> Usenet -> c.d.o.server -> merge join cartesian- access path?
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
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-UNIQUEReceived on Wed Oct 29 1997 - 00:00:00 CST
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