BUG #13774: upgrade from 9.1 to 9.4 'succeeds' without enough disk space

The following bug has been logged on the website:

Bug reference:      13774
Logged by:          Manu Joye
Email address:      manu@coopapotheken.be
PostgreSQL version: 9.4.5
Operating system:   Windows server 2008r2
Description:

running pg_upgrade yields no warnings when there is not enough disk space to
do the upgrade. I  upgraded a server with about 10 databases following the
instructions as provided on the website here. Everything seemed to have gone
well except that some tables in various databases just vanished (pgadmin
complained about missing files) . Upon inspection I noticed the HD had only
a couple of KB of free space left. pg_upgrade seemed to have just restored
what it could and then exited without warning!

We caught it early on and could restore from backups but a check on required
free disk space before upgrade should be implemented or, if that doesn't
work, at least a warning from pg_upgrade that something went wrong.


Kind regards,

Manu

PS I LOVE postgresql, let that be clear. Thanks a whole lot to the whole
team for making this DBMS as awesome as it is.