[p2-dev] p2 profile registry format changes

[John Arthorne <John_Arthorne@xxxxxxxxxx>]

In Galileo SR1 and Helios streams, a
change was made in p2 to compress the profile registry stored on disk [1].
This was a big improvement in the amount of disk space used by p2 metadata
in user installs (roughly 10x reduction of profile registry size). However,
we discovered that people have written tools that manually read or edit
the profile registry stored on disk, and were therefore broken by this
change. Although these are internal metadata files and we don't make attempts
to maintain consistency of these file formats across releases, we want
to give people a heads up about this upcoming change in p2. In addition,
a new system property has been introduced that you can use to revert to
the profile registry format used in previous releases, if desired (for
example in config.ini):

eclipse.p2.profileFormat=uncompressed

Of course using this flag you lose the
benefit of profile compression, but it maintains compatibility for those
manually parsing/editing these files.

John

[1] - https://bugs.eclipse.org/bugs/show_bug.cgi?id=259946