bitmap conversion on a index that is not bitmapped ???

Platform is 8.1.7.4, HP-UX 11.00  

I have a complex view. After rebuilding all indexes this weekend, the view got much faster. I did a trace on it. Now, a few days later, the view is getting much slower. Yes, an analyze has run since then, doing an 'estimate statistics', but an estimate stats was done after the rebuilds as well. The difference in the explain is below - please note that bitmapped conversion info (in bold):  

Good plan:  

..67 .....FIRST ROW
..66 ......VIEW OF 'GAPP_USER. (CARD=1 BYTES=13 )
..65 .......SORT (AGGREGATE) (CARD=1 BYTES=121 )
..64 ........NESTED LOOPS (COST=53 CARD=1 BYTES=121 )
..61 .........TABLE ACCESS (BY INDEX ROWID) OF 'AIF.AIF_OUTBOUND' (COST=51 CARD=1 BYTES=86 )
..60 ..........BITMAP CONVERSION (TO ROWIDS)
..59 ...........BITMAP AND
..55 ............BITMAP CONVERSION (FROM ROWIDS)
..54 .............INDEX (RANGE SCAN) OF 'AIF.AIF_OUTBOUND_IX03' (NON-UNIQUE) (COST=4 )
..58 ............BITMAP CONVERSION (FROM ROWIDS)
..57 .............SORT (ORDER BY)
..56 ..............INDEX (RANGE SCAN) OF 'AIF.AIF_OUTBOUND_IX01' (NON-UNIQUE) (COST=11 )
..63 .........TABLE ACCESS (BY INDEX ROWID) OF 'AIF.EDI_ROUTE' (COST=1 CARD=65 BYTES=2275 )
..62 ..........INDEX (UNIQUE SCAN) OF 'AIF.EDI_ROUTE_PK' (UNIQUE) (CARD=65 )
    Bad plan:  

..61 .....FIRST ROW
..60 ......VIEW OF 'GAPP_USER. (CARD=1 BYTES=13 )
..59 .......SORT (AGGREGATE) (CARD=1 BYTES=121 )
..58 ........NESTED LOOPS (COST=52 CARD=1 BYTES=121 )
..55 .........TABLE ACCESS (BY INDEX ROWID) OF 'AIF.AIF_OUTBOUND' (COST=51 CARD=1 BYTES=86 )
..54 ..........INDEX (RANGE SCAN) OF 'AIF.AIF_OUTBOUND_IX03' (NON-UNIQUE) (COST=3 CARD=1 )
..57 .........TABLE ACCESS (BY INDEX ROWID) OF 'AIF.EDI_ROUTE' (COST=1 CARD=65 BYTES=2275 )
..56 ..........INDEX (UNIQUE SCAN) OF 'AIF.EDI_ROUTE_PK' (UNIQUE) (CARD=65 )
    The interesting thing is, the table in question does not have any bit mapped indexes on it. Some notes on MetaLink show other people questioning the same issue, but no concrete info is given. Any ideas out there?  

TIA.   John

John Fedock
"K" Line America, Inc.
www.kline.com
* john.fedock_at_us.kline.com  

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Author: Fedock, John (KAM.RHQ)
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