File leak?

template1=# BEGIN;
BEGIN
template1=# CREATE TABLE foobar (foo char(10));
CREATE TABLE
template1=# select relname, relfilenode from pg_class where
relname='foobar';
relname | relfilenode
---------+-------------
foobar | 66372
(1 row)

> killall -9 postmaster
> ll data/base/1/
-rw------- 1 hlinnaka hlinnaka 0 Jun 12 15:33 data/base/1/66372

Unless I'm missing something, that file is left there forever. Not such a
big deal with an empty file, but if you create a new table and load it
with data in the same transaction...

Can you guys confirm?

The problem seems to be in storage/smgr.c. The code keeps track of files
created in the transaction in backend memory. That information is lost on
crash, and there is nothing to clean up the mess later.

I wonder if we could clean up those lost files on database recovery or
vacuum. Do we have a list of valid relfilenodes somewhere? Is pg_class
enough?

- Heikki