Re: BUG #17220: ALTER INDEX ALTER COLUMN SET (..) with an optionless opclass makes index and table unusable

On Wed, Oct 13, 2021 at 9:12 AM Michael Paquier <michael@paquier.xyz> wrote:
>
> On Wed, Oct 13, 2021 at 12:06:32AM +0000, Bossart, Nathan wrote:
> > At first glance, it looks like ALTER INDEX .. ALTER COLUMN ... SET
> > uses the wrong validation function.  I've attached a patch where I've
> > attempted to fix that and added some tests.
>
> The gap is larger than than, because ALTER INDEX .. ALTER COLUMN
> .. SET is supported by the parser but we don't document it.  The only
> thing we document now is SET STATISTICS that applies to a column
> *number*.
>
> Anyway, specifying a column name for an ALTER INDEX is not right, no?
> Just take for example the case of an expression which has a hardcoded
> column name in pg_attribute.  So these are not specific to indexes,
> which is why we apply column numbers for the statistics case.  I think
> that we'd better just reject those cases until there is a proper
> design done here.  As far as I can see, I guess that we should do
> things  similarly to what we do for SET STATISTICS with column
> numbers when it comes to indexes.

+1 it should behave similarly to SET STATISTICS for the index and if
someone tries to set with the column name then it should throw an
error.

-- 
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com