From: "Amit Kapila" <amit.kapila16@gmail.com>
> On Fri, Jul 4, 2014 at 7:29 PM, MauMau <maumau307@gmail.com> wrote:
>> [Hypothesis]
>> Why does the connection processing emit WAL?
>>
>> Probably, it did page-at-a-time vacuum during access to pg_database and
> pg_authid for client authentication. src/backend/access/heap/README.HOT
> describes:
>
> I agree with your analysis that it can happen during connection
> attempt.
Thank you. I'm relieved the cause seems correct.
>> But the customer could not reproduce the problem when he performed the
> same archive recovery from the same base backup again. Why? I guess the
> autovacuum daemon vacuumed the system catalogs before he attempted to
> connect to the database.
>>
> One way to confirm could be to perform the archive recovery by
> disabling autovacuum.
Yeah, I thought of that too. Unfortunately, the customer deleted the the
base backup for testing.
> Another thing which I am wondering about is can't the same happen
> even for Read Only transaction (incase someone does Select which
> prunes the page).
I'm afraid about that, too.
Regards
MauMau
