Re: Snapshot too old logging

On Tue, Nov 15, 2016 at 2:21 PM, Kevin Grittner <kgrittn@gmail.com> wrote:
> On Tue, Nov 15, 2016 at 12:43 PM, Robert Haas <robertmhaas@gmail.com> wrote:
>
>> I think it would be better not to include either the snapshot or the
>> block number, and just find some way to reword the error message so
>> that it mentions which relation was involved without implying that all
>> access to the relation would necessarily fail.  For example:
>>
>> ERROR: snapshot too old
>> DETAIL: One or more rows required by this query have already been
>> removed from "%s".
>
> That particular language would be misleading.  All we know about
> the page is that it was modified since the referencing (old)
> snapshot was taken.  We don't don't know in what way it was
> modified, so we must assume that it *might* have been pruned of
> rows that the snapshot should still be able to see.

Oh, yeah.  So maybe "may have already been removed".