Re: determine snapshot after obtaining locks for first statement

On Thu, Dec 17, 2009 at 12:51 PM, Kevin Grittner
<Kevin(dot)Grittner(at)wicourts(dot)gov> wrote:
> Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
>> I'm not very sure what a clearer explanation would look like
>
> As a stab at it, how about?:
>
> This behavior makes Read Committed mode unsuitable for many UPDATE
> or DELETE commands with joins or subqueries

I don't think that's any clearer, though it is more disparaging. :-)

Note we also say: "The partial transaction isolation provided by Read
Committed mode is adequate for many applications, and this mode is
fast and simple to use; however, it is not sufficient for all cases.
Applications that do complex queries and updates might require a more
rigorously consistent view of the database than Read Committed mode
provides."

...Robert