Thread: Why mention to Oracle ?

On 9/20/24 14:36, Marcos Pegoraro wrote:
> Why PostgreSQL DOCs needs to show or compare the Oracle way of doing
> things ?
> 
> I understand that on page Porting from Oracle PL/SQL is ok to mention
> Oracle, but there are other places where it's not needed. Or, if it's ok
> to mention, why not mention SQL Server or MySQL or any other ?
> 

It's not quite clear to me whether your suggestion is to not mention any
other databases ever, or to always mention every existing one. ;-)

I didn't dig into all the places you mention, but I'd bet those places
reference Oracle simply because it was the most common DB people either
migrated from or needed to support in their application next to PG, and
thus were running into problems. The similarity of the interfaces and
SQL dialects also likely played a role. It's less likely to run into
subtle behavior differences e.g. SQL Server when you have to rewrite
T-SQL stuff from scratch anyway.


regards

-- 
Tomas Vondra

Tomas Vondra <tomas@vondra.me> writes:
> On 9/20/24 14:36, Marcos Pegoraro wrote:
>> Why PostgreSQL DOCs needs to show or compare the Oracle way of doing
>> things ?

> I didn't dig into all the places you mention, but I'd bet those places
> reference Oracle simply because it was the most common DB people either
> migrated from or needed to support in their application next to PG, and
> thus were running into problems. The similarity of the interfaces and
> SQL dialects also likely played a role. It's less likely to run into
> subtle behavior differences e.g. SQL Server when you have to rewrite
> T-SQL stuff from scratch anyway.

As far as the mentions in "Data Type Formatting Functions" go, those
are there because those functions are not in the SQL standard; we
stole the API definitions for them from Oracle, lock stock and barrel.
(Except for the discrepancies that are called out by referencing what
Oracle does differently.)  A number of the other references probably
have similar origins.

            regards, tom lane

On 9/20/24 19:31, Marcos Pegoraro wrote:
> Em sex., 20 de set. de 2024 às 12:53, Tom Lane <tgl@sss.pgh.pa.us
> <mailto:tgl@sss.pgh.pa.us>> escreveu:
> 
>     As far as the mentions in "Data Type Formatting Functions" go, those
>     are there because those functions are not in the SQL standard; we
>     stole the API definitions for them from Oracle, lock stock and barrel.
>     (Except for the discrepancies that are called out by referencing what
>     Oracle does differently.)  A number of the other references probably
>     have similar origins.
> 
> 
> All the time we see somebody adding a new function to Postgres core that
> exists in Python or GO or MySQL, but none of them are mentioned on DOCS.
> 

Which Python/Go/MySQL functions we added to Postgres, for example?

AFAIK we're now adding stuff that is either described by SQL standard,
or stuff that's our own invention. Neither cases would benefit from
explaining how other products behave. That's very different from the
interfaces we copied from Oracle.

> I did never use Oracle but I'm almost sure on Oracle DOCS there are no
> mentions of Postgres, right ? Why do we need to mention it ?
> 

I think Tom already explained that we copied a lot of this stuff from
Oracle, so it makes sense to explain in which cases the behavior
differs. I don't see how removing this would help users, it'd very
clearly make life harder for them.

I'm no fan of Oracle corp myself, but I admit I don't quite understand
why you're upset with the handful of places mentioning the product.


regards

-- 
Tomas Vondra

On 9/20/24 19:48, Marcos Pegoraro wrote:
> Em sex., 20 de set. de 2024 às 13:18, David G. Johnston
> <david.g.johnston@gmail.com <mailto:david.g.johnston@gmail.com>> escreveu:
> 
>     It would be a boon to the community if someone were to put together
>     a web/wiki page or mini-app that details this kind of information
>     and, if considered accurate and relevant enough by the community,
>     link to that more globally while also remove the random and
>     incomplete references of this nature from the main documentation. 
>     As it stands the info is at least relevant, and its incompleteness
>     doesn't cause enough grief, IMO, to warrant its outright removal
>     absent there existing an alternative.
> 
> 
> Oracle DOCs or MySQL DOCs or any other have these comparisons ? I don't
> think so, so why does Postgres have to mention it ? 
> 

I fail to see why would "entity X does not do A" be a good reason to not
do A ourselves. Commercial companies may have their own reasons not to
mention competing products, and few of those will likely apply to our
project. And maybe they're wrong to not do that, not us.

> All these places, and others I didn't find, I think it's correct to say
> Postgres' way of doing that, not what is different from Oracle.
> 

IMHO it's quite reasonable to say "we do X, but this other product
(which is what we try to mimic) does Y".


regards

-- 
Tomas Vondra

On Sat, Sep 21, 2024 at 01:50:37PM -0300, Marcos Pegoraro wrote:
> I didn't say no more people are migrating from Oracle, I just say that maybe
> migrations are now coming from other databases, like SQL Server, MySQL, DB2,
> Firebird, Mongo and many others. So why do you document only for those which
> come from Oracle ?
> New Postgres users are today 90% coming from Oracle or 10%, I think we cannot
> have this number exactly. And if nobody knows, why mention any of them ?
> 
> Thanks for your time and I repeat, I just want to get Postgres DOCs better,
> just that.

I suggest you explain what changes would make the docs better (meaing
more useful).

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  When a patient asks the doctor, "Am I going to die?", he means 
  "Am I going to die soon?"