RE: xplan row source 9i
- From: "Christian Antognini" <Christian.Antognini@xxxxxxxxxxxx>
- To: <barb.baker@xxxxxxxxx>
- Date: Fri, 10 Dec 2004 18:07:43 +0100
Hi
>This job runs in under 2 hours on 8.1.7.4, and 6.5 hours on 9.2.0.4
>(both on VMS 7.3-1)
>The data is identical (exact copy of the data files), but the cpu is
>different. It's possible that the cpu difference accounts for all 4
>hours difference.
The 8.1.7 execution plan is the same as in 9.2.0?
>The row source operations shows an index full scan, while the
>execution plan shows 2 index range scans concatenated. My
>understanding is that the row source is what actually occurred.=20
Yes.
>Would the differences between 8i and 9i account for this difference?
Since you don't provide the 8i execution plan isn't possible to answer =
your question.
> Did version 9i do some "bind variable peeking" that 8i did not do?
Yes, bind variables peeking doesn't exists in 8i.
> If so, is there a hint to turn it off?
Setting OPTIMIZER_FEATURES_ENABLE to 8.1.7 or less should disable it.
>select /*+ INDEX(WOD PK_WOD) */ rowid ,WO_KEY ,XRF_KEY
>from
> WOD where (WO_KEY>:b1 or (WO_KEY=3D:b1 and XRF_KEY>=3D:b2))
How much rows are returned if you apply the two restrictions separately?
Chris
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