On Tue, Sep 30, 2014 at 7:01 PM, Josh Berkus <
josh@agliodbs.com> wrote:
>
> On 09/30/2014 02:43 PM, Tom Lane wrote:
> > Fabrízio de Royes Mello <
fabriziomello@gmail.com> writes:
> >> What's your thoughts about we implement IF NOT EXISTS for CREATE INDEX?
> >
> > It's got the same semantic problems as every other variant of CINE.
> >
> > If there were a huge groundswell of demand for it, maybe we'd hold our
> > noses and do it anyway. But I'm against doing it without that.
>
> This isn't the sort of thing there would ever be a clamor of support
> for, because it's just not that visible of a feature. It's more of a
> regular annoyance for those who encounter it. More importantly, adding
> an IF NOT EXISTS to CREATE INDEX would allow complete idempotent "create
> this bunch of tables" scripts, since now the "create index" statements
> could be included. This would be very nice for schema management tools.
>
> I do think it should be name-based. While an "IF NOT EXISTS" which
> checked for a duplicate column declartion would be nice, there's a raft
> of issues with implementing it that way. Users I know are generally
> just looking to avoid getting a transaction-halting error when they run
> the same create index statement twice.
>
Here is the patch... it's name-based.
