Re: pg_dump with tables created in schemas created by extensions

On 08/27/2016 12:37 AM, Tom Lane wrote:
> Martín Marqués <martin@2ndquadrant.com> writes:
>> Looking at this issue today, I found that we are not setting a
>> dependency for an index created inside an extension.
>
> Surely the index has a dependency on a table, which depends on the
> extension?
>
> If you mean that you want an extension to create an index on a table
> that doesn't belong to it, but it's assuming pre-exists, I think
> that's just stupid and we need not support it.
>

I don't see why that would be stupid (and I'm not sure it's up to us to 
just decide it's stupid).

Imagine you use extensions to break the application into modules. You 
have a "basic" extension, with the table, and a "search" extension 
implementing fulltext search on top of that table. Isn't it natural to 
keep the gin indexes in the search extension?

So the basic--1.0.sql will do something like
  CREATE TABLE x ( ...)

and search--1.0.sql would do
  CREATE INDEX y ON x USING gin (z);  CREATE FUNCTION search_objects(..) ...

because the index and function doing the search are somewhat tightly 
coupled. I admit this is just an example and I don't know how many 
people use extensions this way, but I don't see why this would be 
inherently stupid pattern?

I see the current behavior is documented, and I do understand why global 
objects can't be part of the extension, but for indexes it seems to 
violate POLA a bit.

Is there a reason why we don't want the extension/index dependencies?

regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
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