Re: Writeable CTEs and empty relations

On 2010-02-09 01:09 +0200, Tom Lane wrote:
> Marko Tiikkaja <marko.tiikkaja@cs.helsinki.fi> writes:
>> I traced this down to heapam.c, which has this:
>> ...
>> This doesn't exactly work anymore since we modify the snapshot after
>> calling ExecInitScan().
> 
> So don't do that.  The executor is generally entitled to assume that
> parameters given to ExecutorStart are correct.  In particular, changing
> the snapshot after the query has started to run seems to me to ensure
> all sorts of inconsistent and undesirable behavior.

You do remember that the whole patch in its current form depends on
modifying the snapshot?


Regards,
Marko Tiikkaja