Re: pre-MED

I wrote:
> ...  I'm not even real sure what
> all the issues would be, but I'm pretty sure that subplans are just the
> tip of the iceberg.

Another issue is that ruleutils responds to column aliasing, as indeed
it must to generate correct output for rules:

regression=# explain select * from tenk1 a where a.unique1 = 42;                                 QUERY PLAN
                     
 
-------------------------------------------------------------------------------Index Scan using tenk1_unique1 on tenk1
a (cost=0.00..8.27 rows=1 width=244)  Index Cond: (unique1 = 42)
 
(2 rows)

regression=# explain select * from tenk1 a(foo) where a.foo = 42;                                 QUERY PLAN
                      
 
-------------------------------------------------------------------------------Index Scan using tenk1_unique1 on tenk1
a (cost=0.00..8.27 rows=1 width=244)  Index Cond: (foo = 42)
 
(2 rows)

This would be a bit of a problem for dblink or similar functions, which
would have no way at all to know how the column names that they are
dealing in got renamed.
        regards, tom lane