Date: Tue, 3 Jul 2018 10:16:50 +0900
From: Michael Paquier <michael@paquier.xyz>
To: "Yotsunaga, Naoki" <yotsunaga.naoki@jp.fujitsu.com>
Cc: Postgres hackers <pgsql-hackers@postgresql.org>
Subject: Re: automatic restore point
Message-ID: <20180703011650.GD2159@paquier.xyz>
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On Tue, Jul 03, 2018 at 01:07:41AM +0000, Yotsunaga, Naoki wrote:
>> There is also recovery_target_lsn which is new as of v10.
>  In this method, it is necessary to look at a lsn position before operati=
ng.
>  But I assume the user who did not look it before operating.
>  So I think that this method is not appropriate.

You should avoid top-posting on the mailing lists, this breaks the
consistency of the thread.

>> So basically what you are looking for here is a way to enforce a
>> restore point to be created depending on a set of pre-defined
>> conditions?  How would you define and choose those?
>
> I understand that I was asked how to set up a command to apply this funct=
ion.=20
>  Ex) DROP =3D on=20
>      TRUNCATE =3D off
>  Is my interpretation right?
>  If my interpretation is correct, all the above commands will be
>  applied.
>  When this function is turned on, this function works when all the
>  above commands are executed.=20

Yeah, but based on which factors are you able to define that such
conditions are enough to say that this feature is fully-compliant with
user's need, and how can you be sure that this is not going to result in
an additional maintenance burden if you need to define a new set of
conditions in the future.  For example an operator has issued a costly
ALTER TABLE which causes a full table rewrite, which could be also an
operation that you would like to prevent.  Having a set of GUCs which
define such low-level behavior is not really user-friendly.
--
Michael

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