From: Ian Barwick <ian.barwick@2ndquadrant.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Stephen Frost <sfrost@snowman.net>
Cc: pgsql-hackers@postgresql.org <pgsql-hackers@postgresql.org>
Subject: Re: [PATCH] Stop ALTER SYSTEM from making bad assumptions
Date: Wed, 19 Jun 2019 13:39:05 +0900
Message-ID: <75425921-0829-e84a-392e-168081dac6e7@2ndquadrant.com> (raw)
In-Reply-To: <CAA4eK1+gOhcqPdRVUJDLrrZ=oX+dG9e+0TH417F3OazPZAmQEA@mail.gmail.com>
References: <aed6cc9f-98f3-2693-ac81-52bb0052307e@2ndquadrant.com>
<20190614160835.GF2480@tamriel.snowman.net>
<CAA4eK1JW9UfLOtMEJq5b_YcogbWdxzAGUzNi72F2Xx4r1_h6QA@mail.gmail.com>
<20190616171610.GO2480@tamriel.snowman.net>
<27dc9f8d-8d8f-9dd1-0494-5d8bd2f49a45@2ndquadrant.com>
<CAA4eK1+gOhcqPdRVUJDLrrZ=oX+dG9e+0TH417F3OazPZAmQEA@mail.gmail.com>
On 6/19/19 12:46 PM, Amit Kapila wrote:
> On Mon, Jun 17, 2019 at 8:20 PM Ian Barwick <ian.barwick@2ndquadrant.com> wrote:
>> On 6/15/19 1:08 AM, Stephen Frost wrote:
>> > * Amit Kapila (amit.kapila16@gmail.com) wrote:
>> >> Right. I think if possible, it should use existing infrastructure to
>> >> write to postgresql.auto.conf rather than inventing a new way to
>> >> change it. Apart from this issue, if we support multiple ways to edit
>> >> postgresql.auto.conf, we might end up with more problems like this in
>> >> the future where one system is not aware of the way file being edited
>> >> by another system.
>> >
>> > I agere that there should have been some effort put into making the way
>> > ALTER SYSTEM is modified be consistent between the backend and utilities
>> > like pg_basebackup (which would also help third party tools understand
>> > how a non-backend application should be modifying the file).
>>
>> Did you mean to say "the way postgresql.auto.conf is modified"?
>>
>
> Yes, that is what we are discussing here. I think what we can do here
> is to extract the functionality to set the parameter in .auto.conf
> from AlterSystemSetConfigFile and expose it via a function that takes
> (option_name, value) as a parameter.
Yup, I was just considering what's involved there, will reply to another
mail in the thread on that.
> Then we can expose it via some
> SQL function like set_auto_config (similar to what we have now for
> set_config/set_config_by_name). I think if we have something like
> that then pg_basebackup or any other utility can use it in a
> consistent way.
Umm, but the point is here, the server will *not* be running at this point,
so calling an SQL function is out of the question. And if the server
is running, then you just execute "ALTER SYSTEM".
Regards
Ian Barwick
--
Ian Barwick https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
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To: pgsql-hackers@postgresql.org
Cc: ian.barwick@2ndquadrant.com, amit.kapila16@gmail.com, sfrost@snowman.net
Subject: Re: [PATCH] Stop ALTER SYSTEM from making bad assumptions
In-Reply-To: <75425921-0829-e84a-392e-168081dac6e7@2ndquadrant.com>
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