openSUSE: how to disable "delta RPM"

In order to save bandwidth, zypper is set by default to download so-called "delta RPMs", which are basically just binary patches. The process of applying the delta RPM can be, and often is, more time-consuming than downloading the full RPM.

To disable this behavior, edit the /etc/zypp/zypp.conf file. There are lots of options there and one can learn quite a bit just by reading the comments. The option we are interested in is:

##
## Whether to consider using a .delta.rpm when downloading a package
##
## Valid values: boolean
## Default value: true
##
## Using a delta rpm will decrease the download size for package updates
## since it does not contain all files of the package but only the binary
## diff of changed ones. Recreating the rpm package on the local machine
## is an expensive operation (memory,CPU). If your network connection is
## not too slow, you benefit from disabling .delta.rpm.
##
download.use_deltarpm = false

As in the example above, set it to false.