On Thu, 2006-05-11 at 12:18, Jim C. Nasby wrote:
> On Wed, May 10, 2006 at 08:31:54PM -0400, Tom Lane wrote:
> > "Jim C. Nasby" <[EMAIL PROTECTED]> writes:
> > > On Tue, May 09, 2006 at 03:13:01PM -0400, Tom Lane wrote:
> > >> PFC <[EMAIL PROTECTED]> writes:
> > >>> Fun thing is, the rowcount from a temp table (which is the problem 
> > >>> here)  
> > >>> should be available without ANALYZE ; as the temp table is not 
> > >>> concurrent,  
> > >>> it would be simple to inc/decrement a counter on INSERT/DELETE...
> > >> 
> > >> No, because MVCC rules still apply.
> > 
> > > But can anything ever see more than one version of what's in the table?
> > 
> > Yes, because there can be more than one active snapshot within a single
> > transaction (think about volatile functions in particular).
> 
> Any documentation on how snapshot's work? They're a big mystery to me.
> :(

http://www.postgresql.org/docs/8.1/interactive/mvcc.html

Does the concurrency doc not cover this subject well enough (I'm not
being sarcastic, it's a real question)

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