Date: Fri, 15 Mar 2024 09:28:31 -0500
From: Nathan Bossart <nathandbossart@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>,
	Bertrand Drouvot <bertranddrouvot.pg@gmail.com>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: Introduce XID age and inactive timeout based replication slot
 invalidation
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On Thu, Mar 14, 2024 at 12:24:00PM +0530, Amit Kapila wrote:
> On Wed, Mar 13, 2024 at 9:24 PM Bharath Rupireddy
> <bharath.rupireddyforpostgres@gmail.com> wrote:
>> On Wed, Mar 13, 2024 at 9:21 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
>> > > So, how about we turn conflict_reason to only report the reasons that
>> > > actually cause conflict with recovery for logical slots, something
>> > > like below, and then have invalidation_cause as a generic column for
>> > > all sorts of invalidation reasons for both logical and physical slots?
>> >
>> > If our above understanding is correct then coflict_reason will be a
>> > subset of invalidation_reason. If so, whatever way we arrange this
>> > information, there will be some sort of duplicity unless we just have
>> > one column 'invalidation_reason' and update the docs to interpret it
>> > correctly for conflicts.
>>
>> Yes, there will be some sort of duplicity if we emit conflict_reason
>> as a text field. However, I still think the better way is to turn
>> conflict_reason text to conflict boolean and set it to true only on
>> rows_removed and wal_level_insufficient invalidations. When conflict
>> boolean is true, one (including all the tests that we've added
>> recently) can look for invalidation_reason text field for the reason.
>> This sounds reasonable to me as opposed to we just mentioning in the
>> docs that "if invalidation_reason is rows_removed or
>> wal_level_insufficient it's the reason for conflict with recovery".
> 
> Fair point. I think we can go either way. Bertrand, Nathan, and
> others, do you have an opinion on this matter?

WFM

-- 
Nathan Bossart
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