Re: Restore relhaspkey in PostgreSQL Version 11 Beta

On 07/30/2018 04:11 PM, Melvin Davidson wrote:
> 
> 
> On Mon, Jul 30, 2018 at 6:21 PM, Andres Freund <andres@anarazel.de 
> <mailto:andres@anarazel.de>> wrote:
> 
>     Hi,
> 
>     On 2018-07-30 17:21:25 -0400, Melvin Davidson wrote:
>      > * >it has never been the case that relhaspkey meant that the table
>      > *currently* has a primary key. *
> 
>      > *Hmmm, I guess it's a lot harder to fix "squishy semantics"from 
>          "True
>     > if the table has (or once had) a primary key"  to    "True if the table has
>     > a primary key after vacuum"rather than just dropping a column that has
>      > existed from version 7.2.So <http://7.2.So> now I guess the
>     policy is break code instead of
>      > fix documention.That meakes sense...NOT!*
> 
>     A large portion of the system catalogs (i.e. objects within
>     pg_catalog.*) are essentially internal implementation details and we'll
>     change them if it makes our live easier. If you want stability use
>     information_schema which we'll try very hard to not ever break.  Keeping
>     random atavistic things around, would slow us down, which will be a
>     price everybody is paying.
> 
>     Greetings,
> 
>     Andres Freund
> 
> 
> *> If you want stability use information_schema which we'll try very 
> hard to not ever break.
> *
> *Of course. Would you be so kind as to point out where in the 
> information_schema it
> *
> *indicates if a table has a primary key or not. Oh wait, now I 
> remember...no place.*

https://www.postgresql.org/docs/10/static/infoschema-table-constraints.html

"constraint_type     character_data     Type of the constraint: CHECK, FOREIGN 
KEY, PRIMARY KEY, or UNIQUE"

> *
> *
> *>Keeping random atavistic things around, would slow us down, which will 
> be a
>  >price everybody is paying.
> *
> *Random atavistic things? I hardly think relhaspkey is random. It's been 
> there since version 7.2.*
> *Exactly how does keeping it around slow you/us down?
> *
> 
> 
> -- 
> *Melvin Davidson**
> Maj. Database & Exploration Specialist**
> Universe Exploration Command – UXC***
> Employment by invitation only!


-- 
Adrian Klaver
adrian.klaver@aklaver.com