Re: Finer Extension dependencies

Hi,

Thanks for your review!

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> I think the lack of pg_upgrade support is a must-fix before commit.

I though that would only be a TODO for 9.2 to 9.3 upgrades. When
upgrading from 9.1 to 9.2, pg_upgrade will directly stuff extensions
using InsertExtensionTuple() with an empty features list. That will call
insert_extension_features() which ensures that the extension name is
registered as a feature even when not explicitly listed (backward
compatibility with control files).

So I think we're covered now, but still need to revisit the issue later.

I edited the comment this way:

List *features = NIL; /* 9.3 should get features from catalogs */

> Don't we need some psql support for listing the features provided by
> an installed extension? And an available extension?

It's already in the pg_available_extension_versions system's view, which
is not covered by psql (yet). Do we want a new \dx derived command?

> get_extension_feature_oids seems to be misnamed, since it returns only
> one OID, not more than one, and it also returns the feature OID. At a
> minimum, I think you need to delete the s from the function name;
> possibly it should be renamed to lookup_extension_feature or somesuch.

Done.

> List *requires; /* names of prerequisite extensions */
> + List *provides; /* names of provided features */
>
> Comment in requires line of above hunk should be updated to say
> "prerequisite features".

Done.

> -
>
> Useless hunk.

That must be my editor adding a final line when I visit files… and I
can't seem to be able to prevent this hunk from happening?

> + errmsg("parameter \"%s\" must be a
> list of extension names",
>
> This error, which relates to the parsing of the "provides" list, say
> "extension features", and the existing code for "requires" needs to be
> updated to say that as well.

Done.

> + errmsg("extension feature \"%s\"
> already exists [%u]",
> + feature, featoid)));
>
> That [%u] at the end there does not conform to our message style
> guidelines, and I think the rest of the message could be improved a
> bit as well. I think maybe it'd be appropriate to work the name of
> the other extension into the message, maybe something like: extension
> "%s" provides feature "%s", but existing extension "%s" already
> provides this feature

Done.

> +extern char * get_extension_feature_name(Oid featoid);
>
> Extra space.

Fixed.

> + if (strcmp(curreq,pcontrol->name) != 0)
>
> Missing space (after the comma).

Fixed.

> OCLASS_EXTENSION_FEATURE should probable be added to the penultimate
> switch case in ATExecAlterColumnType.

Right, done now.

Regards,
--
Dimitri Fontaine
http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support