Re: Support EXCEPT for TABLES IN SCHEMA publications

Hi Vignesh/Nisha,

IMO, it feels like these patches are doing too much work trying to
protect the user from themselves, and it is even making some
combinations difficult to specify.

Also, there is a lot of logic and many lines of code now just for
checking publication command "inconsistencies".

~

Anyway, I wanted to step back for a moment to reconsider if all this
jumping through hoops is really necessary... I'm not sure that it is.

I've been wondering about something much simpler. There are just 2 rules.

RULE 0: Assume the user knows what they are doing!

RULE 1: Fine-grained clauses take precedence (so anything the user
says about a TABLE takes precedence over whatever they say about a
SCHEMA)

e.g.

FOR TABLES IN SCHEMA s1, TABLE s1.t1; -- OK

⁠FOR TABLES IN SCHEMA s1 EXCEPT(TABLE s1.t1), s1; -- FAIL this is a
self-conflict because the same schema is specified 2 ways

⁠FOR TABLES IN SCHEMA s1 EXCEPT(TABLE s1.t1), TABLE s1.t1; -- FAIL
this is a self-conflict because the same table is excluded/include

FOR TABLES IN SCHEMA s1 EXCEPT(TABLE s1.root), s2 -- OK the tree
exclusion takes precedence, so s2.part is also excluded even though
rest of schema s2 is included

⁠FOR TABLES IN SCHEMA s1 EXCEPT(TABLE parent), s2 -- OK the hierarchy
exclusions (default *) take precedence so s2.child also excluded end
though the rest of schema s2 is included

FOR TABLES IN SCHEMA s1 EXCEPT(TABLE s1.parent), TABLE s2.child -- OK,
hierarchy exclusion would normally exclude s2.child too, but the user
says they want to keep it so it stays

FOR TABLES IN SCHEMA s1 EXCEPT(TABLE ONLY s1.parent), s2 -- OK, the
hierarchy exclusion does not go any further, so s2.child is published
along with everything else in s2.
⁠
~~

- Won't this reduce the amount of implementation code needed?
- Won't this simple precedence rule be easily explained/documented?

Thoughts?

Of course, I might have overlooked some fatal flaw, so feel free to
pop this thought bubble.

======
Kind Regards,
Peter Smith.
Fujitsu Austalia