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Message Posted: Fri, 22 Oct 2004 @ 13:05:52 GMT
<-- Anonymously Posted: Friday, October 22, 2004 08:44 -->
I wanted to confirm something about PIs & SIs
We are on 4700, V2R4. Here is my question:
I have a table with columns, say, COL1, COL2, COL3 & COL4. 85 million rows, approx 10Gs
PI on COL1 & COL2.
SI1 on COL3
SI2 on COL4
SI3 on COL3, COL4
1) I am recommending we can drop SI3 because we have S1 & S2 on the columns. The optimizer will do a bit mapping when both indexes are qualified. Any performance considerations?.
2) Would we gain anything by collecting stats on the PI ?. As per Teradata guidelines, collect stats on PIs only if the table is small. This is not. Any performance considerations if we don't collect stats?.
Thanks, in advance
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