Gregory Stark wrote:
> "Rick Gigger" <rick@alpinenetworking.com> writes:
>
>> I thought that the following todo item just barely missed 8.2:
>>
>> "Allow a warm standby system to also allow read-only statements [pitr]
>> This is useful for checking PITR recovery."
>
> No, nobody worked on it prior to 8.2. Afaik there's still nobody working on
> it. It's not trivial. Consider for example that your read-only query would
> still need to come up with a snapshot and there's nowhere currently to find
> out what transactions were in-progress at that point in the log replay.
>
> There's also the problem that currently WAL replay doesn't take have allow for
> any locking so there's no way for read-only queries to protect themselves
> against the WAL replay thrashing the buffer pages they're looking at.
>
> It does seem to be doable and I agree it would be a great feature, but as far
> as I know nobody's working on it for 8.3.
Thanks again for the update.