Re: Why Adding "+0" Make A Query Run Faster

"Roman Mirzaitov" <rmirzaitov_at_kt.kg> wrote in message news:<aergf6$91iti$1_at_ID-127142.news.dfncis.de>...
> Hi,
>
> adding 0 to column means disabling indexes on that column in RBO
> environment.
> That's why you got different explain plans.

No that can't be a reason, because:

1. He's not using RBO, he's using CBO (on partitioned table, that's the only way).
2. In both of explains for that column is used INDEX RANGE SCAN, which doesn't seem to me like "disabling indexes".

The change between two of them is that CBO decided to use NESTED LOOP using some partitions instead of HASH JOIN through all partitions.

--
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Dusan Bolek, Ing.
Oracle team leader

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