Re: v9.1, DROP TRIGGER IF EXISTS behaving oddly

On 01/13/2016 02:51 PM, David Rowley wrote:
> On 14 January 2016 at 11:32, Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com
> <mailto:adrian(dot)klaver(at)aklaver(dot)com>> wrote:
>
> On 01/13/2016 02:24 PM, Tom Lane wrote:
>
> "Williamson, Michael" <Michael(dot)Williamson(at)tamucc(dot)edu
> <mailto:Michael(dot)Williamson(at)tamucc(dot)edu>> writes:
>
> I'm attempting to drop a trigger that may or may not exist,
> so am using
> the "IF EXISTS" clause. Â This works fine for tables, views,
> functions,
> domains, and types, but for some reason seems to be ignored for
> triggers. Â I'd expect to see more about this online if it
> were a bug,
> so I'm thinking I may be missing something obvious.
>
>
> Example:
> DROP TRIGGER IF EXISTS udf_customer_update_trigger ON customer;
>
>
> Expected Output:
> NOTICE:Â Â trigger "udf_customer_update_trigger" does not
> exist, skipping
>
>
> Observed Output:
> ERROR:Â Â relation "udf_customer_update_trigger" does not exist
>
>
> Environment:
> CentOS 6.6
> postgresql91-server-9.1.14-1PGDG.rhel6.x86_64
>
>
> This has worked the way you're imagining since (I think) 9.4.
> Before
> that the "if exists" semantics only applied to the trigger itself,
> not to the relation.
>
>
> Alright now I am confused. Other then changing table to table_name I
> am not seeing where the below changed. In both cases a NOTICE is
> supposed to be raised.
>
> http://www.postgresql.org/docs/9.1/interactive/sql-droptrigger.html
>
> http://www.postgresql.org/docs/9.4/interactive/sql-droptrigger.html
>
>
> Seems to have been changed in
> http://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=b152c6cd0de1827ba58756e24e18110cf902182a

I will take a look at this at some point. The part that has me confused
from the original post is this:

ERROR: relation "udf_customer_update_trigger" does not exist

If the ERROR is because the table does not exist, why not?:

ERROR: relation "customer" does not exist

>
> Perhaps that commit should have also made changes to the documents to
> change things such as:
>
> Do not throw an error if the trigger does not exist. A notice is issued
> in this case.
>
> To
>
> Do not throw an error if the trigger or table does not exist. A notice
> is issued in this case.
>
> --
> David Rowley http://www.2ndQuadrant.com/
> PostgreSQL Development, 24x7 Support, Training & Services

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com