Re: Duplicate key issue in a transaction block

--- On Mon, 6/8/09, Bill Moran <wmoran(at)potentialtech(dot)com> wrote:

> From: Bill Moran <wmoran(at)potentialtech(dot)com>
> Subject: Re: [GENERAL] Duplicate key issue in a transaction block
> To: "Ioana Danes" <ioanasoftware(at)yahoo(dot)ca>
> Cc: "PostgreSQL General" <pgsql-general(at)postgresql(dot)org>
> Received: Monday, June 8, 2009, 12:33 PM
> In response to Ioana Danes <ioanasoftware(at)yahoo(dot)ca>:
> >
> > Hi Everyone,
> >
> > I have a hard to reproduce scenario for a production
> site....I tried to simplify the code and at the end I could
> get a similar problem with the following table and java
> code.
> > The problem is that I have a transaction that deletes
> all the records in a group and inserts the new records for
> that group. If that transaction is called from 2 different
> clients for the same groupid it happens to get a duplicate
> key violation which it should never happen on my
> opinion!!!!!!!!
>
> On what is that opinion based?  Considering the
> situation you describe, I
> would expect it to error every time you try to run that
> same script twice
> in parallel.

Well, you are right, I had a wrong understanding of Read Committed isolation level. I was expecting that my inserts will see only what was committed before the transaction begin not before the query begin.

Thanks for your answer...

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