Re: Lets (not) break all the things. Was: [pgsql-advocacy] 9.6 -> 10.0

On 12 Apr 2016, at 17:23, Merlin Moncure <mmoncure(at)gmail(dot)com> wrote:
> On Mon, Apr 11, 2016 at 11:39 AM, Justin Clift <justin(at)postgresql(dot)org> wrote:
>> Moving over a conversation from the pgsql-advocacy mailing list. In it
>> Simon (CC'd) raised the issue of potentially creating a backwards-compatibility
>> breaking release at some point in the future, to deal with things that
>> might have no other solution (my wording).
>>
>> Relevant part of that thread there for reference:
>>
>> http://www.postgresql.org/message-id/CANP8+jLtk1NtaJyXc=hAqX=0k+ku4zfavgVBKfs+_sOr9hepNQ@mail.gmail.com
>>
>> Simon included a short starter list of potentials which might be in
>> that category:
>>
>> * SQL compliant identifiers
>> * Remove RULEs
>> * Change recovery.conf
>> * Change block headers
>> * Retire template0, template1
>> * Optimise FSM
>> * Add heap metapage
>> * Alter tuple headers
>> et al
>>
>> This still is better placed on -hackers though, so lets have the
>> conversation here to figure out if a "backwards compatibility breaking"
>> release really is needed or not.
>
> A couple of points here:
> *) I don't think having a version number that starts with 10 instead
> of 9 magically fixes backwards compatibility problems and I think
> that's a dangerous precedent to set unless we're willing to fork
> development and support version 9 indefinitely including major release
> versions.
>
> *) Compatibility issues at the SQL level have to be taken much more
> seriously than other things (like internal layouts or .conf issues).
>
> *) We need to do an honest cost benefit analysis before breaking
> things. Code refactors placed on your users puts an enormous cost
> that is often underestimated. I have some fairly specific examples of
> the costs related to the text cast removal for example. It's not a
> pretty picture.

Yeah. Moving the discussion here was more to determine which items
really would need a backwards compatible break. eg no other approach can
be found.

Seems I started it off badly, as no-one's yet jumped in to discuss the
initial points. :(

+ Justin

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