Re: WIP: Covering + unique indexes.

25.02.2016 21:39, Jeff Janes:
>> As promised, here's the new version of the patch "including_columns_4.0".
>> I fixed all issues except some points mentioned below.
> Thanks for the update patch.  I get a compiler warning:
>
> genam.c: In function 'BuildIndexValueDescription':
> genam.c:259: warning: unused variable 'tupdesc'

Thank you for the notice, I'll fix it in the next update.
> Also, I can't create a primary key INCLUDING columns directly:
>
> jjanes=# create table foobar (a int, b int, c int);
> jjanes=# alter table foobar add constraint foobar_pkey primary key
> (a,b) including (c);
> ERROR:  syntax error at or near "including"
>
> But I can get there using a circuitous route:
>
> jjanes=# create unique index on foobar (a,b) including (c);
> jjanes=# alter table foobar add constraint foobar_pkey primary key
> using index foobar_a_b_c_idx;
>
> The description of the table's index knows to include the including column:
>
> jjanes=# \d foobar
>      Table "public.foobar"
>   Column |  Type   | Modifiers
> --------+---------+-----------
>   a      | integer | not null
>   b      | integer | not null
>   c      | integer |
> Indexes:
>      "foobar_pkey" PRIMARY KEY, btree (a, b) INCLUDING (c)
>
>
> Since the machinery appears to all be in place to have primary keys
> with INCLUDING columns, it would be nice if the syntax for adding
> primary keys allowed one to implement them directly.
>
> Is this something or future expansion, or could it be added at the
> same time as the main patch?

Good point.
At quick glance, this looks easy to implement it. The only problem is 
that there are too many places in code which must be updated.
I'll try to do it, and if there would be difficulties, it's fine with me 
to delay this feature for the future work.

I found one more thing to do. Pgdump does not handle included columns 
now. I will fix it in the next version of the patch.

-- 
Anastasia Lubennikova
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company