Re: BUG #17720: pg_dump creates a dump with primary key that cannot be restored, when specifying 'using index ...'

On 12/15/22 14:18, Daniel Gustafsson wrote:
>> On 15 Dec 2022, at 00:27, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>
>> Daniel Gustafsson <daniel@yesql.se> writes:
>>> The attached prohibits the use of NULLS NOT DISTINCT for backing primary key
>>> constraints but allow them for unique constraints.  Is this along the lines of
>>> what you had in mind?
>>
>> Needs more than zero comments in the code, and why bother testing
>> is_alter_table in index_check_primary_key?  We're disallowing
>> this case across-the-board, no matter how you get to it.
> 
> That was an, admittedly poor, attempt at self-documenting code.  Removed and
> comments added in the attached.

[reviewing patch...]

If the point in adding a primary key USING INDEX is to avoid building an 
index, then this restriction defeats that purpose.  We have no ALTER 
INDEX command to switch or drop the <unique null treatment>.

Since the primary key can't have any nulls anyway, I think we should 
just flip this, perhaps with a NOTICE like the rename does.
-- 
Vik Fearing