Re: dbms_stats.gather... (method_opt)

Walter K wrote:
>
> Hi,
>
> Could someone tell me what the "HIDDEN" columns option
> is in the DBMS_STATS.GATHER_SCHEMA_STATS and
> DBMS_STATS.GATHER_TABLE_STATS procedures? I don't seem
> to find any explanation anywhere about its purpose.
>
> Thanks again.
> -w
>

I would guess that 'hidden' columns may more or less have to do with the object option, which seems (if sys.col$ is to be believed) to sometimes present as a single aggregated column what is indeed traditional 'split' columns. Another possibility might be function-based indexes. They create dummy columns in dba_ind_columns, those dummy (and therefore hidden) columns might be used when gathering stats. Just wild ideas.

-- 
Regards,

Stephane Faroult
Oriole Ltd
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Author: Stephane Faroult
  INET: sfaroult_at_oriole.com

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