pg_database_size issue an error (ERROR: could not stat file "base/16384/20041": Permission denied)

Hi all,
The usage of the pg_database_size function generate a lot of "permission
denied" log errors.
Typical message is: ERROR: could not stat file "base/16384/20041":
Permission denied.

As a short description:
- PostgreSQL 9.2.1/64 bits
- our system is running on windows platform (W7, W2008)
- frequent alter/create/drop of tables
- call to pg_database_size, sometimes.

When logging file system activity (using procmon, W7), the query made on
the file printed in the log message return a “DELETE PENDING” state and i
only find a handle to this file owned by a postgres executable.

After code exploration, it looks like the functions from "dbsize.c" should
use the same trick as found in "md.c" (i mean the FILE_POSSIBLY_DELETED
macro) for testing each "stat()" returned error code.

So, is it a good idea to patch dbsize.c with the same macro, which on
windows platform include the EACCES error code as a possibly deleted file,
or not. Or is it the wrong way ? I didn't try to patch yet.

Thanks for your help,

Christophe