Re: BUG #18637: CREATE INDEX won't look up operator classes in search_path if PARTITION BY is specified

I wrote:
> I have not dug into the code, but I think this may actually be a
> bug; not because of the change of search path, but because it looks
> like the opclass is probably being looked up more than once during
> the command, with different search paths. That has security
> implications, and not good ones. We should fix this so that the
> opclass is looked up exactly once, and passed down to the partitions
> by OID not name.

Here's an example that doesn't rely on any outside extension:

regression=# create extension cube;
CREATE EXTENSION
regression=# create table items(category_id int, val cube) partition by list(category_id);
CREATE TABLE
regression=# CREATE INDEX ON items (val cube_ops);
CREATE INDEX
regression=# CREATE TABLE id_123 PARTITION OF items FOR VALUES IN (1, 2);
CREATE TABLE
regression=# CREATE INDEX items_idx_2 ON items (val cube_ops);
ERROR: operator class "cube_ops" does not exist for access method "btree"

So that's pretty awful: creating the partitioned index by itself is
willing to look up the opclass in the current search path, and then
adding a new partition will play nice with that, but creating a
partitioned index when there's already a partition will not.
It's got to be considered a bug that the two paths for making a
child index behave differently.

As far as I understand, the change of search path is only supposed to
affect user-defined code within the expressions of an expression index.
Operands of the command itself should consistently be interpreted in
the current search path.

regards, tom lane