Re: CREATE IF NOT EXISTS INDEX

On Tue, Sep 30, 2014 at 9:12 PM, Josh Berkus <josh(at)agliodbs(dot)com> wrote:
>
> On 09/30/2014 04:58 PM, Fabrízio de Royes Mello wrote:
> > On Tue, Sep 30, 2014 at 8:47 PM, Josh Berkus <josh(at)agliodbs(dot)com> wrote:
> >>
> >> On 09/30/2014 04:16 PM, Andres Freund wrote:
> >>> On 2014-09-30 16:03:01 -0700, Josh Berkus wrote:
> >>>> On 09/30/2014 03:53 PM, Andres Freund wrote:
> >>>>> Good point. I think it's fair enough to only allow CINE on named
> >>>>> indexes.
> >>>>
> >>>> On the other hand, the way we form system-generated names is
> > predicable,
> >>>> so I think it would be perfectly OK to include them. Desirable, in
> > fact.
> >>>
> >>> It's not really that predicable. Think about expression indexes. They
> >>> also don't contain information about opclasses et all.
> >>>
> >>> Seems like pit of hairy semantics.
> >>>
> >>>> Not that I'm a fan of omitting the name ...
> >>>
> >>> Me neither.
> >>
> >> I'd be OK with a CINE which required you to name the index.
> >>
> >> How does your patch work at present, Fabrizio?
> >>
> >
> > My patch will work just if you name the index, because postgres
generates a
> > index name that doesn't exists.
> >
> > I don't check to a name if we use IF NOT EXISTS, but I can add this
check.
>
> The consensus is that we don't want IF NOT EXISTS to work for
> automatically generated index names. For that reason, we'd want it to
> error out if someone does this:
>
> CREATE INDEX IF NOT EXISTS ON table(col);
>
> My suggestion for the error message:
>
> "IF NOT EXISTS requires that you name the index."
>

Done.

--
Fabrízio de Royes Mello
Consultoria/Coaching PostgreSQL
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