Re: How to use read uncommitted transaction level and set update order

From: "Andrus" <kobruleht2(at)hot(dot)ee>
To: "Christophe Pettus" <xof(at)thebuild(dot)com>
Cc: <pgsql-general(at)postgresql(dot)org>
Subject: Re: How to use read uncommitted transaction level and set update order
Date: 2009-12-20 09:12:39
Message-ID: DEA9201791A244A0894EB6823BC192CF@andrusnotebook
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> You cannot access new values of a particular row within a single UPDATE
> statement, but you do see new values done in the same transaction.
> This is explain in some detail in the documentation:
>
> http://www.postgresql.org/docs/8.4/interactive/transaction-iso.html#XACT-READ-COMMITTED

I tried

drop table if exists tt ;
create temp table tt ( a int, b int );
insert into tt values ( 1,2);
insert into tt values ( 3,4);
update tt set a=a*10, b=(select sum(a) from tt);
select * from tt

b has value 4 for every row.

So we *dont* see new values done in the same transaction.
How to fix ?

Andrus.

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