Re: Distributed Query in 8i->9i now slower 9i->9i

"Lee Van Doren" <leevd_at_adelphia.net> wrote in message news:afc7da8f.0402270853.5cb843a3_at_posting.google.com...
> An 8i database PLRU is linked to a 9i database SBGS
>
> We exported all data tables from PLRU into PLRS, a 9i database.
> We established a link from PLRS to SBGS.
>
> A distributed query that runs across PLRU-SBGS (8i-9i) runs in 17s.
> Running the same query in PLRS-SBGS (9i-9i) runs in 15 MINUTES.
>
> From everything we can tell the equivalent configurations are present
> between the two databases.
> The explain plan on each execution show some differences. Notably the
> faster query shows it utilizing several MB of memory for one step
> while the slower query never chooses to use more than 111K for any
> step. Is there something making it think it doesnt have much memory
> to work with?
> The faster plan also shows it using MERGE JOIN CARTESIAN while the
> slower plan doesn't use that option.
>
> Also, queries running internally on PLRS (9i) run on average TWICE as
> FAST as PLRU (8i).
>
> I also minimized the query down to mainly just working with the remote
> tables and see the same type of behavior. The two plans are closer to
> each other but still a big difference in the faster plan taking
> advantage of memory while the slower plan will not.
>
> What could be different?
> The data is the same in both databases and they are on equivalent
> sized servers with equivalent configured data and memory.
> Note that the SBGS database is on the same physical machine as the
> PLRS database (even though it is the slower combination).
>
> Any ideas?
> Lee

Basically your post runs down to
'It doesn't work, why?'
If you provide me your crystall ball, I will tell you. Your post doesn't contain anything but vague statements.

-- 
Sybrand Bakker
Senior Oracle DBA

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