Re: row cache lock contention parallel insert

  • From: Greg Rahn <greg@xxxxxxxxxxxxxxxxxx>
  • To: exriscer@xxxxxxxxx
  • Date: Sat, 19 Dec 2009 10:01:27 -0800

I dont recall the bug# but there is an issue related to quotas that
can show when there are a relatively high number of concurrent PX
sessions inserting into the same tablespace.  The work around is to do
a direct grant (dba or unlimited quota sys priv is not sufficient).
alter user <name> quota unlimited on <ts>;

That may be enough for you to find the bug (look for the dc row cache
stuff also).

Hope that helps.

On Fri, Dec 18, 2009 at 11:58 PM, LS Cheng <exriscer@xxxxxxxxx> wrote:
>
> The insert is simply insert append into... select, the degree of parallelism
> is 8 for some tables, 4 for others and 2 for smaller tables. I can observe
> that when there are 5 of these inserts running concurrently all of them
> suffers high contention on row cache lock, specifically dc_object_ids and
> dc_segments. Previously the load processes ran without parallel DML and
> yesterday pdml was enabled. Same symptoms.

-- 
Regards,
Greg Rahn
http://structureddata.org
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