Subject: Re: dealing with extension dependencies that aren't quite
 'e'
To: Abhijit Menon-Sen <ams@2ndQuadrant.com>, <pgsql-hackers@postgresql.org>
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From: Jim Nasby <Jim.Nasby@BlueTreble.com>
Message-ID: <56D4F6B7.8010200@BlueTreble.com>
Date: Mon, 29 Feb 2016 19:56:07 -0600
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On 2/29/16 7:27 PM, Abhijit Menon-Sen wrote:
> 1. This adds the 'x'/DEPENDENCY_AUTO_EXTENSION type.
> 2. This adds an 'ALTER FUNCTION … ADD DEPENDENT FUNCTION …' command.
>
> I split up the two because we may want the new dependency type without
> going to the trouble of adding a new command. Maybe extension authors
> should just insert an 'x' row into pg_depend directly?

I don't see why this would be limited to just functions. I could 
certainly see an extension that creates ease-of-use views that depend on 
the extension, or tables that have triggers that .... Am I missing 
something?

> I was inclined to implement it using ALTER FUNCTION, but AlterFunction()
> is focused on altering the pg_proc entry for a function, so the new code
> didn't fit. Ultimately, ExecAlterExtensionContentsStmt() was the closest
> match, so that's where I did it.

Maybe the better way to handle this would be through ALTER EXTENSION?

Given the audience for this, I think it'd probably be OK to just provide 
a function that does this, instead of DDL. I'd be concerned about asking 
users to do raw inserts though. pg_depends isn't the easiest thing to 
grok so I suspect there'd be a lot of problems with that, resulting in 
more raw DML to try and fix things, resulting in pg_depend getting 
completely screwed up...
-- 
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
Data in Trouble? Get it in Treble! http://BlueTreble.com


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