Re: possible to use an exceptions table in parallel?
- From: "Jared Still" <jkstill@xxxxxxxxx>
- To: ricks12345@xxxxxxxxx
- Date: Mon, 23 Jun 2008 11:30:42 -0700
Should you wish to try this method, the parallel hint syntax was incorrect.
It should be */*+ parallel (my_tab,4) */*
I really should have RTFM'd that. :)
On Mon, Jun 23, 2008 at 9:37 AM, Jared Still <jkstill@xxxxxxxxx> wrote:
>
> On Mon, Jun 23, 2008 at 6:24 AM, Rick Ricky <ricks12345@xxxxxxxxx> wrote:
>
>> http://www.jlcomp.demon.co.uk/faq/duplicates.html
>>
>> I do not know how to do an
>>
>> 'alter table add unique constraint' in parallel.
>>
>> the only way I know how to use parallel is with a 'create index'. Problem
>> is 'exceptions into' does not seem to work with this statement.
>>
>> I have a big table. Anyway to use the exceptions table with the parallel
>> clause? if not it will run for hours.
>>
>
>
> It appears that you are using the EXCEPTIONS clause just to locate
> duplicates.
>
> If so, you may be able to use another method.
>
> You could use select with group by to find the duplicates
>
> select my_col
> from my_tab
> group by my_col
> having_count > 1;
>
> Theoretically you can add a parallel hint to the query to run it in
> parallel
>
> select /*+ parallel my_tab(4) */ my_col
> from my_tab
> group by my_col
> having_count > 1;
>
> I say theoretically because I don't see a parallel query happening when I
> use it on test 10gR2 db.
>
> When I modify the table with 'alter table tablename parallel 4' I do get
> the
> parallel query.
>
> Modifying the table is likely not an option however.
>
> Getting the parallel hint to work may require some research.
>
> The 10gR2 docs say the hint will override the table settings, but I don't
> see it happening.
>
> Probably an oversight on my part, but this is just to give you an idea for
> an alternative method anyway.
>
>
> --
> Jared Still
> Certifiable Oracle DBA and Part Time Perl Evangelist
>
--
Jared Still
Certifiable Oracle DBA and Part Time Perl Evangelist
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