sql: ALTER TABLE commands can incorrectly become no-ops

[solongordon]

Due to some bad accounting of whether the table descriptor has changed, ALTER TABLE sometimes does not perform the requested changes.

[email protected]:61248/movr> create table t (x int, y int);
CREATE TABLE

[email protected]:61248/movr> alter table t rename column x to x2, rename column y to y;
ALTER TABLE

[email protected]:61248/movr> show create table t;
  table_name |          create_statement
-------------+-------------------------------------
  t          | CREATE TABLE public.t (
             |     x INT8 NULL,
             |     y INT8 NULL,
             |     FAMILY "primary" (x, y, rowid)
             | )

[solongordon]

Note this only affects ALTER TABLE commands with multiple operations where the last operation has no effect. (And only certain operations at that.)