Re: SR fails to send existing WAL file after off-line copy

On 02.11.2010 00:47, Tom Lane wrote:
> Greg Stark<gsstark(at)mit(dot)edu> writes:
>> On Mon, Nov 1, 2010 at 12:37 AM, Heikki Linnakangas
>> <heikki(dot)linnakangas(at)enterprisedb(dot)com> wrote:
>>> Yes, indeed there is a corner-case bug when you try to stream the very first
>>> WAL segment, with log==seg==0.
>
>> This smells very much like
>> http://article.gmane.org/gmane.comp.db.postgresql.devel.general/137052
>
>> I wonder if there's some defensive programming way to avoid bugs of this sort.
>
> It strikes me that it's not good if there isn't a recognizable "invalid"
> value for WAL locations. These bits of code show that there is reason
> to have one. Maybe we should teach initdb to start the WAL one segment
> later, and then 0/0 *would* mean "invalid", and we could revert these
> other hacks.

Good idea. That can even be back-patched to 9.0, it should have no
effect on existing installations,

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com