Re: Duplicate values found when reindexing unique index

Simon Riggs <simon(at)2ndquadrant(dot)com> writes:
> On Mon, 2007-12-31 at 11:53 -0500, Tom Lane wrote:
>> The state of the ...0058 file might be explained by the theory that
>> you'd archived it a bit too late (after the first page had been
>> overwritten with newer WAL data),

> The interlock with .ready and .done should prevent reuse of a file. So
> the only way this could happen is if the archive_command queued a
> request to copy, rather than performing the copy immediately.
> So I was going to say "thats not possible", but perhaps rsync might
> become confused by the file renaming mechanism we use?

Actually, the other problem with that theory is that the slave swallowed
the file without complaint. Since the WAL reader code does check that
the page header contains the expected address, this seems to imply that
what the slave saw must have had 422/58 in it, not the 423/C1 we see
now. So what needs to be explained is why what Mason is looking at now
is different from what the slave saw ten days ago.

regards, tom lane