Re: Maximum number of transaction. (Newby question).

"VC" <boston103_at_hotmail.com> wrote in message news:31e0625e.0310300645.4c908003_at_posting.google.com...
> Hello Ben,
>
> The behaviour you're observing is explained by Oracle 9i's creating
> _two_ ITL slots instead of one despite your specifying 'initrans 1'.
> It can be easily verified by dumping the data block.
>
> If you perform an update #3 on row #3 in addition to the two you've
> already initiated, you'll get the desired effect.
>
> Rgds.
>

Thanks I immediatly tried it and this explains the behavior of the Oracle database. Not the dumping but using a third session.

I think that the Oracle documentation fails here, because most docs (that I have read) do not explain this correctly. Learning from books which explain something false and then trying these things is not easy.

This effect probably explains a deadlock I have experienced in the past. (When I asked about this on an Oracle course they couldn't give any explanation about deadlocks concerning totaly 'disconnected' sessions not sharing any data. This does explain that. Although I still do not know if this really was the cause).

Thanks for taken the time to answer,

ben brugman

>
> "ben brugman" <ben_at_niethier.nl> wrote in message
news:<3fa0f04d$0$245$4d4ebb8e_at_read.news.nl.uu.net>...
> > At the moment I am playing around with an Oracle database.
> >
> > I have set The number of transactions for a test table
> > initial to 1 and maximum to 1.
> > I enter 3 small rows into a table.
> > (All rows end up in the same block, when selecting with rowid
> > all is the same except that the last digit becomes A or B or C).
> >
> > Now I open a session and do an update on the first row.
> > I open a second session and do an update on the second row.
> >
> > Both updates succeede and I can commit both.
> > Because of the only one transaction in a block I would expect that
> > one transaction would be blocked by the first.
> >
> > What am I missing or understanding wrongly.
> >
> > ben brugman
Received on Thu Oct 30 2003 - 12:02:13 CST