Thread: Changing column filter for existing publication with WAL backlog

Hi,

Recently, I decided to add column filtering for our publication. The commands I used were:
ALTER SUBSCRIPTION mysub DISABLE;

ALTER PUBLICATION mypub SET TABLE public.my_table(id, first_column, another_column), TABLE public.other_table; -- excluding third_column

ALTER SUBSCRIPTION mysub ENABLE;

When I tested this approach in our staging environment, it worked as expected – I stopped seeing updates to third_column. However, in production I still see updates to that column. I also ran ALTER SUBSCRIPTION mysub REFRESH PUBLICATION after noticing that updates were still being replicated.

Could this behavior be due to the large WAL backlog in production? At the time I applied the column filter, the replication lag was around 4 TB (with total storage being 16 TB). Should I expect that once production catches up to WAL records generated after the change, updates to third_column will eventually stop replicating?

Thanks in advance for your help.