Re: Select Fetching from UNDO

Dear Gurus,

It will be great help if i could get some light on it .

Regards,
Krishna

On Tue, 5 Sept 2023 at 12:13, Krishnaprasad Yadav <chrishna0007_at_gmail.com> wrote:

> Dear Gurus,
>
> we see a performance issue and Application team provided session id ,
> we tried to figure out the detail and understand that session was executing
> one select statement , going further we see that most of the reads activity
> happening on UNDO tablespace for select statement , want to understand is
> fetching all records from UNDO is normal behavior or i should look for any
> rollback too or on which aspect such situation get raised .
>
>
>
> File ID % Activity Event % Event
> --------------- ---------- ------------------------------ ----------
>
> Tablespace
> -----------------------------------------------------
> -------------------------
> 4237 5.30 db file sequential read 3.31
> UNDOTBS2
>
> gc cr disk read 1.49
>
>
> 4238 4.97 db file sequential read 2.90
> UNDOTBS2
>
> gc cr disk read 1.74
>
>
> 4258 4.06 db file sequential read 2.24
> UNDOTBS2
>
> gc cr disk read 1.66
>
>
> 4239 3.73 db file sequential read 2.24
> UNDOTBS2
>
> gc cr disk read 1.16
>
>
> 4257 3.48 db file sequential read 2.40
> UNDOTBS2
>
>
> Regards,
> Krishna
>

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