Re: [HACKERS] [PATCH] Document the order of changing certain settingswhen using hot-standby servers - Mailing list pgsql-hackers

From Robert Haas
Subject Re: [HACKERS] [PATCH] Document the order of changing certain settingswhen using hot-standby servers
Date
Msg-id CA+TgmoaAKRv+t_=gsQhLC0+uk4++ejK3z1D2XLubugxCgHHaDw@mail.gmail.com
Whole thread Raw
In response to Re: [HACKERS] [PATCH] Document the order of changing certain settingswhen using hot-standby servers  (Yorick Peterse <yorickpeterse@gmail.com>)
Responses Re: [HACKERS] [PATCH] Document the order of changing certain settingswhen using hot-standby servers  (Peter Eisentraut <peter.eisentraut@2ndquadrant.com>)
List pgsql-hackers
On Thu, Apr 13, 2017 at 8:29 AM, Yorick Peterse <yorickpeterse@gmail.com> wrote:
> Good point, right now it can give you the idea that applying it to just
> 1 standby (instead of all of them) is good enough, when instead you
> need to apply it to all of them.
>
> Attached is an adjusted version of my changes to better reflect this.

To me, this just seems redundant.  The existing documentation already says:
    For these parameters,    the value on the standby must    be equal to or greater than the value on the primary. If
theseparameters    are not set high enough then the standby will refuse to start.
 

Now you're proposing to add:
   If you want to increase these values you   should do so on all standby servers first, before applying the changes to
 the primary. If you instead want to decrease these values you should do so   on the primary first, before applying the
changesto all standby servers.
 

But that's just the obvious logical consequence of the existing statement.

If we're going to add this text, I'd move it one sentence earlier and
stick "Therefore, " at the beginning.  But it strikes me that it's
just a bet that if we say things twice instead of once, people will
pay more attention -- which is maybe true, but if that's done on a
widespread basis, it will cause the documentation to become bloated.

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



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