Hi Pierre, On 3/2/18 6:36 AM, Pierre Ducroquet wrote: > > While working on a big table recently, I noticed that ALTER TABLE does not > check for column existence in operations like SET NOT NULL before starting > working on the table, for instance adding a primary key. > It is thus possible, if a typo has been made, to generate a long lock and a > lot of WAL that will serve no purpose since the whole transaction will be > discarded. > > For example : > > toto=# alter table test add primary key(i), alter column typo set not null; > ERROR: column "typo" of relation "test" does not exist > Time: 10.794 s > > The attached patch fixes this behaviour by adding a small check in the first > pass of alter table to make sure that a column referenced by an alter command > exists first. It also checks if the column is added by another alter sub- > command. It does not handle every scenario (dropping a column and then > altering it for instance), these are left to the exec code to exclude. > The patch has been checked with make check, and I see no documentation change > to do since this does not alter any existing documented behaviour.
This looks like a good idea. However, the last CF for PG11 is in progress so it might be difficult to attract much comment/review right now. I recommend entering this patch in the 2018-09 CF so it doesn't get lost. Regards, -- -David da...@pgmasters.net
