Re: Ignore histograms on sql level

Jonathan, I don't think that's possible. Optimizer first collects the object information which can be manipulated by column_stats, index_stats and opt_estimate hints. Only after that does the optimizer check the histograms to determine the actual cardinalities of the row sources. OPT_PARAM hint, mentioned by Tanel, is probably the only way of bypassing histograms except dropping them using DBMS_STATS.

Regards

On 1/19/21 2:47 PM, Jonathan Lewis wrote:
>
> I'm just wondering whether some form of the column_stats() hint could
> override the use of the histogram.
>
> Regards
> Jonathan Lewis
>
>
> On Tue, 19 Jan 2021 at 06:25, Tanel Poder <tanel_at_tanelpoder.com
> <mailto:tanel_at_tanelpoder.com>> wrote:
>
> Hi Moustafa,
>
> If you really need to do this at SQL level, you could use
> *opt_param* hint with *_optimizer_use_histograms = false*.
>
> But it would make this query ignore all histograms, not just one
> on a specific column:
>
>

-- 
Mladen Gogala
Database Consultant
http://mgogala.byethost5.com


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