Thanks Greg,

 

But doesn't gather_system_stats populate sys.aux_stats$ and hence is consistent throughout the cluster?

 

Thanks

Fairlie

Greg Rahn < greg@structureddata.org> wrote:

The object stats would be the same, but it is possible for the system
stats to be different. Have you validated they are consistent across
nodes? Perhaps it would be best to snag the system stats that produce
the good plan and import them to the other nodes.

On 6/6/07, fairlie rego wrote:
> Hi all,
>
> I have a query which has a good plan on one node (node 3) and a bad plan
> (node 1) caused by a Merge Join Cartesian on another.
>
> Bind variable peeking is disabled and dynamic sampling is disabled for this
> query. There is no difference in v$sql_optimizer_env for the query across
> the 2 nodes.
>
> In the 10053 output I see a difference in RSC_IO for fast full scan of
> indexes which I thought was based on the leaf blocks and blevel. Given that
> the stats across nodes are the same how can this happen?. If this is due to
> varying load because of workarea_size_policy how do we protect ourselves.
>
> I can send the 10053 outputs but here is one snippet
>
> Node 3
> ======
> Access Path: index (index-ffs)
> Index: ADVANCED_FILTER_PK
> rsc_cpu: 875652262 rsc_io: 8606
> ix_sel: 0.0000e+00 ix_sel_with_filters: 1.0000e+00
>
> Node 1
> ======
> Access Path: index (index-ffs)
> Index: ADVANCED_FILTER_PK
> rsc_cpu: 875652262 rsc_io: 26521
> ix_sel: 0.0000e+00 ix_sel_with_filters: 1.0000e+00
>
>
> Thanks
> Fairlie


--
Regards,

Greg Rahn
http://structureddata.org

Fairlie Rego
Senior Oracle Consultant

http://el-caro.blogspot.com/

M: +61 402 792 405

 

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