Re: Sort/Merge problem

"Ben" <balvey_at_comcast.net> writes:

> Oracle Ent Ed. 9.2.0.5, AIX5L
>
> came in this morning to 3 ora-1652 errors.
>
> I'm checking to see what is using all my temp space and there are 5
> processes running the same select statement that each have almost 1 Gig
> of TEMP space.
>
> When I look at the Long Operation of those processes it is a
> Sort/Merge, and the explain plan shows a select that has an indexed
> column in the predicate and is ordering by four other columns that make
> up the primary key.
>
> Forgive my ignorance but why does this cause a Sort/Merge? Is it the
> fact that it is binding by one index and sorting by a different index?
>

[...]

Hello Ben,

ordering by varchar2 columns does not use any index unless nls_sort is set to binary.
Normally, Oracle has locale specific sort orders that are different from the binary order of the index.

Hope that helps,
Lothar

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