Hello Viktor, There was a known slowness issue in this view.It was fixed in PG 10: https://www.postgresql.org/message-id/flat/2d533e5b-687a-09fa-a772-dac9e6cf9...@imap.cc#2d533e5b-687a-09fa-a772-dac9e6cf9...@imap.cc You can try to use a solution from there to create a faster view that returns the same data as information_schema.constraint_column_usage. I wouldn't be surprised if it was safe to replace information_schema.constraint_column_usage itself, but I cannot guarantee it.
Best, Alex
