[PATCH] Re: BUG #16032: pg_basebackup when running on Windows doesn't clean up on failure correctly

Hello,

I've already posted this to pg_hackers, but I'm not sure if it's more
normal to
post proposed fixes against the bug itself; so see attached if needed.

Thanks,
Rob

On 2019-10-01 17:06, PG Bug reporting form wrote:
> The following bug has been logged on the website:
>
> Bug reference: 16032
> Logged by: Rob Emery
> Email address: postgresql(at)mintsoft(dot)net
> PostgreSQL version: 11.5
> Operating system: Windows
> Description:
>
> Hello,
>
> When running a pg_basebackup in tar mode on windows against a PG 9.5
> box we
> are finding that the backup doesn't get deleted successfully when it
> fails.
> Based on
> https://github.com/postgres/postgres/commit/9083353b15c3cf8e7bbac104a81ad42281178cdf#diff-473d306e41ee616e92fb58ac128a9dcc
> we would expect it to?
>
> To reproduce start running pg_basebackup like so:
>
> PS C:\Users\developer> & "$PgBinPath\pg_basebackup.exe"
> --host="PGSERVER"
> --pgdata="D:\Backups\rofl" --format=tar --wal-method=fetch
> --username="backup_user"
>
> from a psql on the box run:
> `SELECT pg_terminate_backend(pid) FROM pg_stat_replication WHERE state
> =
> 'backup';`
> this kills the backup.
>
> If you run pg_basebackup on a linux box it nicely deletes the base.tar
> and
> the directory, whereas on windows we get the following error:
> ```
> pg_basebackup: could not read COPY data: SSL SYSCALL error: EOF
> detected
> pg_basebackup: removing data directory "D:\Backups\rofl"
> could not remove file or directory "D:\Backups\rofl/base.tar":
> Permission
> denied
> could not remove file or directory "D:\Backups\rofl": Directory not
> empty
> pg_basebackup: failed to remove data directory
> ```
> Once pg_basebackup has exited, the file lock seems to be gone and we
> can
> delete it ourselves,
> it looks like pg_basebackup is contending with itself but only on
> Windows.
>
> We've reproduced this on 2 different Windows machines so we don't think
> it's
> something like AntiVirus getting in the way or similiar.
>
> Thanks,
> Rob