Re: remove more archiving overhead

On Thu, Jul 07, 2022 at 10:46:23AM -0400, David Steele wrote:
> On 7/7/22 10:37, Robert Haas wrote:
>> On Thu, Jul 7, 2022 at 10:03 AM Fujii Masao <masao(dot)fujii(at)oss(dot)nttdata(dot)com> wrote:
>> > Thanks for updating the patch. It looks good to me.
>> > Barring any objection, I'm thinking to commit it.
>>
>> I don't object, but I just started to wonder whether the need to
>> handle re-archiving of the same file cleanly is as well-documented as
>> it ought to be.
>
> +1, but I don't think that needs to stand in the way of this patch, which
> looks sensible to me as-is. I think that's what you meant, but just wanted
> to be sure.

Yeah, this seems like something that should be documented. I can pick this
up. I believe this is an existing problem, but this patch could make it
more likely.

> There are plenty of ways that already-archived WAL might get archived again
> and this is just one of them.

What are some of the others? I was aware of the case that was fixed in
ff9f111, where we might try to re-archive a file with different contents,
but I'm curious what other ways you've seen this happen.

--
Nathan Bossart
Amazon Web Services: https://aws.amazon.com