Re: merging some features from plpgsql2 project

On 12/28/16 7:16 AM, Pavel Stehule wrote:
> ** The real problem is that we have no mechanism for allowing a PL's
> language/syntax/API to move forward without massive backwards
> compatibility problems. **
>
>
> We have not, but there are few possibilities:
>
> 1. enhance #option command
> 2. we can introduce PRAGMA command
> https://en.wikipedia.org/wiki/Ada_(programming_language)#Pragmas
> <https://en.wikipedia.org/wiki/Ada_%28programming_language%29#Pragmas>

I wanted to break this out separately, because IMO it's the real heart
of the matter.

I think it would be silly not to allow a global setting of
compatibility. You certainly don't want to force people to stick magic
keywords in their code forevermore.

To that end, would GUCs be a workable answer here? That should give you
the ability to control incompatibilities at a function, user, database
and global level. It would also allow you to chose between raising a
WARNING vs a FATAL.

I realize we've had some bad experiences with compatibility GUCs in the
past, but I'd argue we've also had some good experiences. I see that
add_missing_from is now completely gone, for example, presumably with no
complaints. There's probably several other compatibility GUCs we could
remove now.
--
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
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