Re: what is the meaning of statistic_name='space_used' in v$segment_statistics?

  • From: Gerwin Hendriksen <gerwin.hendriksen@xxxxxxxxx>
  • To: baziel@xxxxxxxxxx
  • Date: Wed, 6 Oct 2010 15:23:24 +0200

Hi Baziel,

I think the problem here is a column overflow as sometimes happens with for
example the statistic "redo size" in v$sesstat, when the number are getting
really big, above 4294967296 (32 bit border), the number wents to negative.

Regards,

Gerwin

2010/10/6 Baziel de Leeuw <baziel@xxxxxxxxxx>

> Hi,
>
> What does the statistic_name='space used' column in v$segment_statistics
> show?
>
> I get results i don't understand at all, e.g.
>
> SQL> select owner, object_name, statistic_name, value from
> v$segment_statistics where owner='SYS' and
> object_name='WRI$_OPTSTAT_HISTGRM_HISTORY' and statistic_name='space used';
>
> OWNER      OBJECT_NAME                    STATISTIC_NAME
> VALUE
> ---------- ------------------------------ ---------------
> ------------------
> SYS        WRI$_OPTSTAT_HISTGRM_HISTORY   space used
> -554110
>
> Yes, that is a negative value.
>
> I expected beforehand that space_used would be something like bytes in
> memory or something like that.
>
> Does anyone know what it actually is?
>
> Baziel
>
>
>

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