Re: ITL and possible deadlocks

Michael,

thanks for your response.
I meant the following situation. Transaction#1 updates a row#1 in block#1 of a table. In order to do
it allocates a ITL slot.
Transaction#2 updates a row#100 in block#100 of the same table and also allocates transaction slot.
If there is no free space to allocate additional ITL slots in these blocks then other transactions
can't modify these blocks until transaction#1 and transaction#2 do commit or rollback. Then
transaction#1 tryes to update row#101 in the block#100 and transaction2 tryes to update row#2 in the block#1. Both transaction have to wait because there are no empty ITL slots. You
can see that there are no share rows and each transaction updates its own rows. How Oracle resolve such case?

Ed

> Ed,
>
> Not sure that I understood it right, but I'll take a try.
> So there are 2 transactions and each one is trying to update the row which was
>already updated by

the other transaction?
> IMHO, if you are trying to place an exclusive lock on the locked row ( it remains
>locked until

commit ), you either wait or receive
> an error if "no wait" was specified.
> Behaviour of the 2nd transaction is trying to place an exclusive lock on the 1st
>transaction' row

is just the same.
> If both transactions wait, it's a deadlock situation and should be resolved by
>Oracle itself.
>
> HTH,
> Michael Netrusov,
> www.atelo.com
>
>
> ----- Original Message -----
> To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com>
> Sent: Tuesday, March 20, 2001 10:40
>
>
> > Hello List,
> >
> > it's rather a theoretical question. Let say two sessions
> > update a table. Each transaction allocated a transaction
> > slot in a block (I consider the two different blocks).
> > Each block has only one slot and there is no free space
> > in these blocks to allocate additional transaction slots.
> > Then each transaction tryes to update a row in the block
> > which has already been updated by the other transaction.
> > How Oracle to do with such situation in case when there is
> > no access to a common resource (I mean a common row) ?
> >
> >
> > Thanks in advance
> >
> > Ed
> > --
> > Please see the official ORACLE-L FAQ: http://www.orafaq.com
> > --
> > Author: Shevtsov, Eduard
> > INET: EShevtsov_at_flagship.ru
> >
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> Author: Michael Netrusov
> INET: mn_at_g-fax.com
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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Shevtsov, Eduard
  INET: EShevtsov_at_flagship.ru

Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051
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