Re: Significance of specific database parameter difference

The first two non default parameters ( _buffered_publisher_flow_ control_threshold , _capture_publisher_flow_control_threshold =500000) are streams specific and help to improve streams performance in certain scenarios , but as streams are desupported in 19C so those should not matter. And apart from those two , other 10 parameters which you mentioned , i would suggest to go by the defaults only. My 2 cents.

Regards
Lok

On Tue, Apr 20, 2021 at 4:35 PM Pap <oracle.developer35_at_gmail.com> wrote:

> Hello All, we are moving from HP to Exadata - X8. Along with this we are
> also moving from current Oracle version 11.2.0.4 to 19C. And below are a
> few of the differences in parameters we see between old and new databases.
> New database(which is not yet live) holds mostly default setup only. But
> the existing database has below non default setup(Around ~12 parameters),
> And I don't know if those non default setups in the old/existing database
> is really helping us anyway. So wanted to understand if it's safe to go by
> all the defaults(as it's mentioned below) for the new database? Or any of
> these non default parameters from existing databases is really critical to
> be double checked/verified thoroughly, so that we may need to move those as
> it is to the new database?
>
>
> *Existing environment (11.2, HP):- *
>
> _buffered_publisher_flow_control_threshold = 500000
>
> _capture_publisher_flow_control_threshold =500000
>
> _enable_query_rewrite_on_remote_objs = true
>
> _optimizer_cost_based_transformation = linear
>
> nls_sort = 'BINARY'
>
> optimizer_dynamic_sampling=0
>
> optimizer_index_caching=100
>
> optimizer_index_cost_adj=1
>
> optimizer_secure_view_merging=FALSE
>
> query_rewrite_enabled=FALSE
>
> optimizer_mode=FIRST_ROWS
>
> session_cached_cursors=0
>
>
> *New environment- (19C, Exadata - X8):- *
>
> _buffered_publisher_flow_control_threshold = null
>
> _capture_publisher_flow_control_threshold =null
>
> _enable_query_rewrite_on_remote_objs = NULL
>
> _optimizer_cost_based_transformation = null
>
> nls_sort =NULL
>
> optimizer_dynamic_sampling=2
>
> optimizer_index_caching=0
>
> optimizer_index_cost_adj=100
>
> optimizer_secure_view_merging=TRUE
>
> query_rewrite_enabled=TRUE
>
> optimizer_mode=ALL_ROWS
> session_cached_cursors=200
>

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