If a table is dropped from pg_class accidentally then how to restore it from backup?

Question

I accidentally dropped a table from pg_class and I have the same table present in a different server inside a schema. How do I restore it?

I have tried this

psql -U {user-name} -d {desintation_db} -f {dumpfilename.sql}`

This is what i'm getting -

ERROR:  type "food_ingredients" already exists`
HINT:  A relation has an associated type of the same name, so you must use a name that doesn't conflict with any existing type.`
ERROR:  relation "food_ingredients" does not exist`
ERROR:  syntax error at or near "19411"`
LINE 1: 19411 10405 2074 45.3333333333 0.17550085492131515 NULL NULL...`
ERROR:  relation "food_ingredients" does not exist`

food_ingredients is the table which I dropped from the pg_class.

Answer 1

That's what you get from messing with system catalogs.

The simple and correct answer is “restore from a backup”, but something tells me that that's not the answer you were looking for.

You could drop the type that belongs to the table, all indexes on the table, all constraints, toast tables and so on, but you'd probably forget to drop something or drop something you shouldn't and end up with a bigger mess than before.
Moreover, the table file would be left behind and it would be hard to identify and delete it.

It would be appealing to try and recreate the pg_class row that you dropped, but you wouldn't be able to create it with the correct oid since you cannot directly insert a certain oid or update that column.

You could dump the whole database cluster with pg_dumpall, create a new cluster with initdb and restore the backup there, but this might fail because of the data inconsistencies.

Really, the best thing is to restore a backup.