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Understanding ODCIStatsIndexCost results in 10053 trace [message #65699] Thu, 09 December 2004 08:41
Tim Scott
Messages: 1
Registered: December 2004
Junior Member
I'm trying to pin down why a Text index isn't being used consistently and to this end obtained some 10053 traces to examine.
For the correct query plan the ODCIStatsIndexCost routine returned (CPU 1, IO 75, Net 0). Shortly after this in the 10053 trace output there is a line stating "Cost 475 Selectivity 0", followed closely by "BEST_CST 474.65".
How does (1,75,0) become 474.65? What else is involved?
For the much less than optimal query plan the ODCIStatsIndexCost routine returned (1,1,0). This was followed by "Cost 70260 Selectivity 0", "BEST_CST 70259.94 ..".
How does (1,1,0) become 70259.94? What else is involved?
The first is from Oracle 8.1.7 on Solaris; the second from 8.1.7 on Windows.
Thanks very much for any help or pointers given on this.
Tim
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