Re: [HACKERS] [PostgreSQL 10] default of hot_standby should be "on"?

Поиск
Список
Период
Сортировка
От Michael Banck
Тема Re: [HACKERS] [PostgreSQL 10] default of hot_standby should be "on"?
Дата
Msg-id 20170503141835.GA20909@nighthawk.caipicrew.dd-dns.de
обсуждение исходный текст
Ответ на Re: [HACKERS] [PostgreSQL 10] default of hot_standby should be "on"?  (Magnus Hagander <magnus@hagander.net>)
Ответы Re: [HACKERS] [PostgreSQL 10] default of hot_standby should be "on"?  (Magnus Hagander <magnus@hagander.net>)
Список pgsql-hackers
Hi,

On Tue, May 02, 2017 at 11:13:58AM +0200, Magnus Hagander wrote:
> Looks good to me as well. Applied, with only a minor further docs addition
> saying that this is the default also on the high availability page.

I understand this is late, but a colleague alerted me to the following
behaviour change: If you recover a server with default settings, it is
our understanding that pg_isready will now return true immediately after
the consistent state is reached and possibly well before recovery had
actually ended (depending on the amount of outstanding wal). As hot
standby works with log shipping, this is independent of the
recovery.conf settings, i.e. even if standby_mode and primary_conninfo
are not set. So if one was monitoring recovery like that before and
expects pg_isready to only return true once the recovery is fully
complete, this will now have to be adjusted. Also, if the recovered
server is to be used for transactions, there will now be a window where
the server accepts connections, but is in read-only mode.

Before, one had the make the concious choice to set hot_standby to get
the behaviour, now it might be surprising to users, or maybe I'm
overthinking this?

If that is indeed the case, maybe it should be mentioned more
prominently in the documentation and/or get highlighted in the release
notes?


Michael

-- 
Michael Banck
Projektleiter / Senior Berater
Tel.: +49 2166 9901-171
Fax:  +49 2166 9901-100
Email: michael.banck@credativ.de

credativ GmbH, HRB Mönchengladbach 12080
USt-ID-Nummer: DE204566209
Trompeterallee 108, 41189 Mönchengladbach
Geschäftsführung: Dr. Michael Meskes, Jörg Folz, Sascha Heuer



В списке pgsql-hackers по дате отправления:

Предыдущее
От: Tom Lane
Дата:
Сообщение: Re: [HACKERS] check with serial
Следующее
От: Claudio Freire
Дата:
Сообщение: Re: [HACKERS] CTE inlining