Re: full usefullness of CURRENT OF ???

Repeat after me...readers never block writers...writers never block readers...

The update will lock the row(s) of the result set, but it will not block anyone from reading the data. However, they may not read the modifications made by the update until it is committed.

MaryAnn Atkinson wrote:
>
> --- Chris Stephens <ChrisStephens_at_affina.com> wrote:
> > Also, the CURRENT OF locks the table so that no one can modify (or
> > even read) it while the transaction is taking place. This guarantees
> > nothing is changing between retrieving values from the cursor and
> > updating the table based on those values.
>
> OK, fair enough.
>
>
> > The second example has to run the update statement seperately.
> > CURRENT OF can go directly to the row(s) affected. CURRENT OF
> > still has to modify each block header in the table to lock which
> > is a small performance hit.
>
> So CURRENT OF has to lock, so its slower, right?
> Does it have any advantages after all?
>
> >To prevent that you could update by rowid
> How? How can I update by ROWID? I was thinking to update
> by PRIMARY_KEY...
>
> > and avoid the header updates.
>
> ... what "header" updates?
>
> thx
> maa
>
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