Re: [Admin] Deleting Orphan Relfilenode

Rahul Saha <rahul(dot)blooming(at)gmail(dot)com> writes:
> We have a scenario where we ran Vacuum Full (2 TB Table)but due to some reason Vacuum Full failed.
> These have let almost 1 TB orphan Relfilenodes inside base directory under the concern database which does not map with pg_class.

Hm, by "fail" do you mean a database crash? Ordinary errors should have
rolled back the file creation successfully.

> For example - Select * from pg_class where relfilenode = 123456. It does not return any row but those relfilenode exist inside base.

I would not trust that query if I were you --- it will not find mapped
system catalogs. Maybe you are certain that this orphaned file wasn't
for a system catalog, but I'd still recommend using

select * from pg_class where pg_relation_filenode(oid) = 123456;

to be sure. (See also contrib/oid2name.)

> It would be great if you can suggest how to remove those orphan files. I know definitely manually deleting is not suggested so thought to know your suggestions.

If they're really orphaned, as proven by a pg_relation_filenode() check,
then manual "rm" is the thing to do. Postgres doesn't know they are
there and will not remove them.

regards, tom lane