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Home -> Community -> Mailing Lists -> Oracle-L -> Re: parallel Pnnn
Lien
You have setup the "parallel query option" (and not "parallel server option").
Parallel query allows to parallise certain SQL-Statements on different
processors on a multi-processor box. (Full table scans, sorts, sub-queries,
etc.)
This option is mainly used for performance reasons.
Parallel server allows to set up multiple instances on different boxes sharing the same disks (a VAX CLUSTER is a typical sample). This option is mainly used for high availability reasons. (Performance can be worse for example in non partitionned OLTP environments)
Bye the way:
Both options must be licensed (Dollar...), at least here in Switzerland.
We do recommend testing the parallel query option carefully, as several clients have found some quiet serious bugs. (For ex. under Oracle 7.1.3 on Vax OpenVMS)
Regards, Andri
At 11:51 07.02.96 +0000, you wrote:
>So what's the difference between parallel query and parallel server? My
>init.ora has:
>
>parallel_max_servers=20
>parallel_min_servers=6
>
>No 'shared' but certainly 'parallel'. v$thread shows:
>
> THREAD# STATUS ENABLED GROUPS INSTANCE OPEN_TIME
> ---------- ------ -------- ---------- ---------------- --------------------
> 1 OPEN PUBLIC 4 CP_PRD 01/21/96 22:30:47
>
>Is this parallel server? I'm confused.
> -----------
>Pnnn processes are Parallel Query processes NOT Parallel Server processes.
>Parallel Server processes look like ora_lck0_SID. These are the Distributed
>lock manager interface processes.
>
>You don't have these lock files unless you start your intance with the
>'shared'
>or 'parallel' options.
>
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