Re: Re: Clarifying "server starting" messaging in pg_ctl start without --wait

From: Robert Haas <robertmhaas(at)gmail(dot)com>
To: Stephen Frost <sfrost(at)snowman(dot)net>
Cc: Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com>, Fujii Masao <masao(dot)fujii(at)gmail(dot)com>, Ryan Murphy <ryanfmurphy(at)gmail(dot)com>, Beena Emerson <memissemerson(at)gmail(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Re: Clarifying "server starting" messaging in pg_ctl start without --wait
Date: 2017-01-18 20:47:32
Message-ID: CA+TgmoYv3xbFNOmsg15ja--mCHUpFs4CYzrPjMHtAgV2QJegiA@mail.gmail.com
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On Wed, Jan 18, 2017 at 3:43 PM, Stephen Frost <sfrost(at)snowman(dot)net> wrote:
> * Robert Haas (robertmhaas(at)gmail(dot)com) wrote:
>> On Tue, Jan 17, 2017 at 5:31 PM, Stephen Frost <sfrost(at)snowman(dot)net> wrote:
>> > If I'm understanding your concern correctly, you're worried about the
>> > case of a cold standby where the database is only replaying WAL but not
>> > configured to come up as a hot standby and therefore PQping() won't ever
>> > succeed?
>>
>> I think we've changed the defaults to make things better for an
>> attended startup and worse for an unattended startup. But I think
>> most PostgreSQL startups are probably unattended.
>
> I don't understand how it's worse for an unattended startup to tell the
> init system that the database is now up and running when, in fact, it
> isn't.
>
> If that isn't what you meant, then it would be really helpful if you
> could explain a bit more what you see as being "worse" with this change
> for unattended startup.

This seems clear as day to me, so I'm not sure what to explain.
Anybody who has got a script that runs pg_ctl unattended mode likely
now has to go update that script to add --no-wait. If they don't,
their script may hang for whatever the timeout is (currently 60
seconds, and it sounds like Peter wants to change that to infiniity).
If they have been wanting their script to hang all along, as you seem
to be saying, then they'll be happy that it now does. If, on the
other hand, they don't want that, then they'll be sad.

In short, I bet we will get multiple reports of people getting hosed
by this change.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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