Re: v$transaction.cr_gets

On Jul 5, 4:13 pm, Chuck <skilover_nos..._at_bluebottle.com> wrote:
> DA Morgan wrote:
> > Chuck wrote:
> >> sybra..._at_hccnet.nl wrote:
> >>> On Fri, 29 Jun 2007 18:05:07 GMT, Chuck
> >>> <skilover_nos..._at_bluebottle.com> wrote:
>
> >>>> What exactly does this column represent? The docs simply say
> >>>> 'Consistent
> >>>> gets'. Is it all consistent gets for the transaction? Or is it just
> >>>> gets
> >>>> that required rolling back a change from the undo segment listed in the
> >>>> xidusn column?
>
> >>> Please read up on what consistent gets are.
>
> >> Please reread the question. Your smug answers are not helpful.
>
> > Before you jump on Sybrand you might want to spend the 10-15
> > seconds required to look up the definition of "consistent gets"
> > in the Oracle docs. It really is self-explanatory and there
> > really is nothing smug or unhelpful about Sybrand's response.
> > It is not his, or anyone else's, responsibility to do your
> > tahiti search for you. You were pointed to the correct answer
> > and it couldn't be more straight-forward unless English is not
> > a language with which you are comfortable.
>
> I already know what consistent gets are. They are blocks read in
> consistent mode - which means they may or may not have required reading
> an undo block to construct a read-consistent view of the data. So once
> again back to my question - Are the consistent gets referenced in
> v$transaction all consistent gets for the transaction, or are they just
> the ones needed to be rolled back from the undo segment also referenced
> on the same row of v$transaction. The Oracle documentation on this
> column - which I did read - is extremely lacking.- Hide quoted text -
>
> - Show quoted text -

Please stop asking rhetorical questions. Obviously the consistent gets are the consistent gets for the transaction. Why would the column have been called consistent_gets otherwise? Because if you look at the definition of v$transaction, there is used_ublk and used_rec. This is the number of blocks and bytes actually changed.
These columns will decrement when a transaction is rolled back.

--
Sybrand Bakker
Senior Oracle DBA