Re: pg and transactions

What are your actual queries? What version of Postgresql?
Are you using FOR UPDATE in your select statements?

/Oskar

On Sat, 28 Dec 2002, pginfo wrote:

> Hi,
>
> I think I have problem with pg transactions ( or I do not understend how
> it work).
>
> I have two connections ( running on java clients via jdbc).
>
> I have one simple table tableA (ID int, value float8 ) with one record
> (1,1000).
>
> And make this steps:
>
> Connection1-> begin transaction
> Connection1-> read the record from tableA ( select values from tableA
> where ID = 1). It returns 1000.
> Connection1-> increase the value to 1001.
> Connection1-> update the new value in tableA by update tableA set value
> = 1001 where ID = 1.
> Connection2-> begin transaction
> Connection2-> read the record from tableA ( select values from tableA
> where ID = 1). It returns 1000. !!!
> Connection2-> increase the value with 1. It gives 1001.
> Connection2-> update the new value in tableA by update tableA set value
> = 1001 where ID = 1.
> Connection2->commit.
>
> do some other jobs with connection1.
>
> Connection1->commit
>
> Actualy I use the table as a simple counter for unique values and I
> expect that Connection2 will wait until Connection1 finish the task.
> Is it normal for pg to work so with transactions?
> If yes how can I lock all the tables after beginning the transaction?
> If no where can I make mistake?
>
> The same example is working well on oracle and all the task is to port
> one oracle based application to pg.
>
> Many tanks and regards,
> ivan.
>
>
>
>
>
>
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