Re: Stupid question on Read Committed Isolation Level - Mailing list pgsql-hackers

From Chris Bowlby
Subject Re: Stupid question on Read Committed Isolation Level
Date
Msg-id 1075400182.92943.28.camel@morpheus.hub.org
Whole thread Raw
In response to Re: Stupid question on Read Committed Isolation Level  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Stupid question on Read Committed Isolation Level
List pgsql-hackers
Would this not create the potention for a dead lock if transaction1 is
never completed, and still active for an indefinate period of time?

On Thu, 2004-01-29 at 14:06, Tom Lane wrote:
> "Marc G. Fournier" <scrappy@hub.org> writes:
> > What happens if I abort on the first transaction?  If I'm reading this
> > right, if Trans2 does the exact same as above, and COMMITs before Trans1
> > Aborts, the value of balance becomes +200 (Trans2 + Trans1) ... but what
> > happens when Trans1 ABORTS?  Trans2 believes its COMMIT worked, but
> > ABORTng Trans1 will rollback to the original value, no?
> 
> If trans2 is the second to get to the row, it will *wait* until trans1
> either commits or aborts, and then use the new or old version of the row
> accordingly.  The scenario you are thinking of can't happen.
> 
>             regards, tom lane
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 7: don't forget to increase your free space map settings
-- 
Chris Bowlby <chris@pgsql.com>
PostgreSQL Inc.



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