commit cfb75203221ad1939bd370274397530b85cc3b81
author David Ostrovsky <david@ostrovsky.org> Sat Oct 31 16:09:42 2015 +0100
committer David Ostrovsky <david.ostrovsky@gmail.com> Mon Jan 25 14:12:59 2016 +0000
tree 0d2e4b4321a037470253d7a0790e95bbeab187ff
parent 70e4a9024abdbc1585ab017f8723c4dda39e3589

Replace AccountGeneralPreferences entity with git backend (phase 1)

Replace the usage of AccountGeneralPreferences with a different class
in extension API package.

To support live migration, the upgrade is done in two steps:

* phase 1 (this change):
  o Always write to both git and db
  o Introduce new configuration option to indicate whether to read from
    git or db, initially set to read from db
  o First binary update: some servers are reading/writing just the db;
    some servers are additionally writing to git
  o After first update: all servers are reading from the db, writing to
    both
  o Batch copy data from db to git (only related to non open source
    Gerrit version)
  o Update all servers to read from git. During the update, some will
    still be reading from the db; that's ok, because everybody is
    writing to git
  o OutgoingEmail class is retrieving copy_self_on_email preference
    always form the database (by getting AccountGlobalPreferences from
    the account cache). This is OK, because all servers are writing to
    the database
* phase 2 (next change):
  o Bump database version, migrate the data from db to git, delete the
    entity (and the flag) from the code and update the servers.

Change-Id: I218d92465665afa0caa01e88ff1fa87f773383eb