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  1. FDW table hints

    Magnus Hagander <magnus@hagander.net> — 2011-05-02T19:27:08Z

    postgres=# DROP TABLE FOO;
ERROR:  "foo" is not a table
HINT:  Use DROP FOREIGN TABLE to remove a foreign table.
postgres=# CREATE INDEX baz ON foo(bar);
ERROR:  "foo" is not a table

To some, that would be confusing - foo kind of is a table, just a
different kind. Should we have some HINT on that one as well?

-- 
 Magnus Hagander
 Me: http://www.hagander.net/
 Work: http://www.redpill-linpro.com/

  2. Re: FDW table hints

    David Fetter <david@fetter.org> — 2011-05-02T21:56:01Z

    On Mon, May 02, 2011 at 09:27:08PM +0200, Magnus Hagander wrote:
> postgres=# DROP TABLE FOO;
> ERROR:  "foo" is not a table
> HINT:  Use DROP FOREIGN TABLE to remove a foreign table.
> postgres=# CREATE INDEX baz ON foo(bar);
> ERROR:  "foo" is not a table
> 
> To some, that would be confusing - foo kind of is a table, just a
> different kind. Should we have some HINT on that one as well?

Until we can actually create indexes on foreign tables, yes ;)

Cheers,
David (Local indexes?  Foreign indexes?  Both?)
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  3. Re: FDW table hints

    Magnus Hagander <magnus@hagander.net> — 2011-05-03T07:30:26Z

    On Mon, May 2, 2011 at 23:56, David Fetter <david@fetter.org> wrote:
> On Mon, May 02, 2011 at 09:27:08PM +0200, Magnus Hagander wrote:
>> postgres=# DROP TABLE FOO;
>> ERROR:  "foo" is not a table
>> HINT:  Use DROP FOREIGN TABLE to remove a foreign table.
>> postgres=# CREATE INDEX baz ON foo(bar);
>> ERROR:  "foo" is not a table
>>
>> To some, that would be confusing - foo kind of is a table, just a
>> different kind. Should we have some HINT on that one as well?
>
> Until we can actually create indexes on foreign tables, yes ;)

Well, yeah, but I don't think we can squeeze that into 9.1 without
Robert noticing :P

Any suggestions on *what* the hint should be? Just something along the
line "indexes cannot be created on foreign tables"?


-- 
 Magnus Hagander
 Me: http://www.hagander.net/
 Work: http://www.redpill-linpro.com/

  4. Re: FDW table hints

    Susanne Ebrecht <susanne@2ndquadrant.com> — 2011-05-03T09:33:26Z

    On 03.05.2011 09:30, Magnus Hagander wrote:
> Well, yeah, but I don't think we can squeeze that into 9.1 without
> Robert noticing :P
>
> Any suggestions on *what* the hint should be? Just something along the
> line "indexes cannot be created on foreign tables"?

Magnus,

I am not really sure if this is clever.

When we make such a hint for foreign tables then we should make a similar
hint for views.

Just my 2ct,

Susanne

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  5. Re: FDW table hints

    Dave Page <dpage@pgadmin.org> — 2011-05-03T09:42:30Z

    On Tue, May 3, 2011 at 10:33 AM, Susanne Ebrecht
<susanne@2ndquadrant.com> wrote:
> On 03.05.2011 09:30, Magnus Hagander wrote:
>>
>> Well, yeah, but I don't think we can squeeze that into 9.1 without
>> Robert noticing :P
>>
>> Any suggestions on *what* the hint should be? Just something along the
>> line "indexes cannot be created on foreign tables"?
>
> Magnus,
>
> I am not really sure if this is clever.
>
> When we make such a hint for foreign tables then we should make a similar
> hint for views.

A view really isn't a table, unlike a foreign table, so I don't think
that argument holds.


-- 
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  6. Re: FDW table hints

    David Fetter <david@fetter.org> — 2011-05-03T12:39:05Z

    On Tue, May 03, 2011 at 10:42:30AM +0100, Dave Page wrote:
> On Tue, May 3, 2011 at 10:33 AM, Susanne Ebrecht
> <susanne@2ndquadrant.com> wrote:
> > On 03.05.2011 09:30, Magnus Hagander wrote:
> >>
> >> Well, yeah, but I don't think we can squeeze that into 9.1 without
> >> Robert noticing :P
> >>
> >> Any suggestions on *what* the hint should be? Just something along the
> >> line "indexes cannot be created on foreign tables"?
> >
> > Magnus,
> >
> > I am not really sure if this is clever.
> >
> > When we make such a hint for foreign tables then we should make a
> > similar hint for views.
> 
> A view really isn't a table, unlike a foreign table, so I don't
> think that argument holds.

There are other systems where it's possible to constrain VIEWs,
something we might approach with an index.  One of those systems comes
from some outfit in Redwood Shores, California with cylindrical
buildings, so it's not as wild as it first appears.

Anyhow:

+1 for mentioning that at the moment, it's not possible to create an
index on a foreign table.

+1 also for doing this with VIEWs, but as a separate patch.

Cheers,
David.
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  7. Re: FDW table hints

    Tom Lane <tgl@sss.pgh.pa.us> — 2011-05-03T14:19:55Z

    Dave Page <dpage@pgadmin.org> writes:
> On Tue, May 3, 2011 at 10:33 AM, Susanne Ebrecht
> <susanne@2ndquadrant.com> wrote:
>> When we make such a hint for foreign tables then we should make a similar
>> hint for views.

> A view really isn't a table, unlike a foreign table, so I don't think
> that argument holds.

Well, from the implementation standpoint a foreign table is a lot more
like a view than it is like a table.  I think the real point is that a
hint for this on views would be a waste of translator manpower, because
we've not heard of anyone making that mistake.

			regards, tom lane

  8. Re: FDW table hints

    Magnus Hagander <magnus@hagander.net> — 2011-05-05T17:14:10Z

    On Tue, May 3, 2011 at 16:19, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Dave Page <dpage@pgadmin.org> writes:
>> On Tue, May 3, 2011 at 10:33 AM, Susanne Ebrecht
>> <susanne@2ndquadrant.com> wrote:
>>> When we make such a hint for foreign tables then we should make a similar
>>> hint for views.
>
>> A view really isn't a table, unlike a foreign table, so I don't think
>> that argument holds.
>
> Well, from the implementation standpoint a foreign table is a lot more
> like a view than it is like a table.  I think the real point is that a
> hint for this on views would be a waste of translator manpower, because
> we've not heard of anyone making that mistake.

The *implementation* is in this case, IMHO; irrelevant. The relevant
part is what it looks like to the *user*, and to the user a foreign
table looks a lot more like a table than a view does.

Since I brought it up - a patch along this line?

-- 
 Magnus Hagander
 Me: http://www.hagander.net/
 Work: http://www.redpill-linpro.com/

  9. Re: FDW table hints

    Tom Lane <tgl@sss.pgh.pa.us> — 2011-05-05T17:22:18Z

    Magnus Hagander <magnus@hagander.net> writes:
> Since I brought it up - a patch along this line?

Please don't capitalize "foreign table" there.

Also, I think an "else" before the other ereport would make the code
clearer, even though it's not strictly necessary.

			regards, tom lane

  10. Re: FDW table hints

    Magnus Hagander <magnus@hagander.net> — 2011-05-05T17:26:09Z

    On Thu, May 5, 2011 at 19:22, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Magnus Hagander <magnus@hagander.net> writes:
>> Since I brought it up - a patch along this line?
>
> Please don't capitalize "foreign table" there.

Yeah, I was a bit split about that myself. Will change.


> Also, I think an "else" before the other ereport would make the code
> clearer, even though it's not strictly necessary.

Agreed.

Unless someone objects, I'll go put that in later tonight. (along with
a comment on why there are two different msgs)

-- 
 Magnus Hagander
 Me: http://www.hagander.net/
 Work: http://www.redpill-linpro.com/

  11. Re: FDW table hints

    Magnus Hagander <magnus@hagander.net> — 2011-05-05T19:48:14Z

    On Thu, May 5, 2011 at 19:26, Magnus Hagander <magnus@hagander.net> wrote:
> On Thu, May 5, 2011 at 19:22, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Magnus Hagander <magnus@hagander.net> writes:
>>> Since I brought it up - a patch along this line?
>>
>> Please don't capitalize "foreign table" there.
>
> Yeah, I was a bit split about that myself. Will change.
>
>
>> Also, I think an "else" before the other ereport would make the code
>> clearer, even though it's not strictly necessary.
>
> Agreed.
>
> Unless someone objects, I'll go put that in later tonight. (along with
> a comment on why there are two different msgs)
>

Done.

-- 
 Magnus Hagander
 Me: http://www.hagander.net/
 Work: http://www.redpill-linpro.com/