Re: Problems with "pg.dropped" column after upgrade 9.5 to 9.6

On Wed, Nov 2, 2016 at 3:32 PM, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> wrote:
> 2016-11-01 22:56 GMT+01:00 Pavel Hanák <hanak(at)is-it(dot)eu>:
>> Can anybody explain what is the problem?
>
> please, can you send test case - I cannot to reproduce this bug on master.

I can reproduce the regression on master and 9.6:
DROP TABLE aa;
CREATE TABLE aa (a int, b int, c int);
CREATE OR REPLACE FUNCTION _test_sql_update(in do_update boolean)
RETURNS VOID LANGUAGE sql VOLATILE AS $$
update aa
set a = NULL
where do_update;
$$;
INSERT INTO aa VALUES (generate_series(1,1,1));
INSERT INTO aa VALUES (generate_series(2,1,1));
INSERT INTO aa VALUES (generate_series(3,1,1));
ALTER TABLE aa DROP COLUMN b;
SELECT _test_sql_update(false);
SELECT _test_sql_update(true);

I am just digging into it... An interesting part is that removing the
WHERE clause makes the regression go away.
--
Michael