Merge lp:~stub/charms/trusty/postgresql/standby-service into lp:charms/trusty/postgresql

[Stuart Bishop]

The last landing broke PostgreSQL < 9.4 installs using the default configuration options.

Fix this by downgrading unsupported wal_level's when necessary. This seems preferable to changing the default, which would mean requiring the wal_level to be set before the new relation type would actually work.

[Stuart Bishop (stub)]

review: Abstain

[Tim Van Steenburgh (tvansteenburgh)]

LGTM.

review: Approve

=== modified file 'hooks/hooks.py'
--- hooks/hooks.py	2015-07-09 18:35:13 +0000
+++ hooks/hooks.py	2015-07-10 11:12:07 +0000
@@ -414,6 +414,12 @@
     host.write_file(postgresql_sysctl, ''.join(lines), perms=0600)
     _run_sysctl(postgresql_sysctl)
 
+    # Our config file specifies a default wal_level that only works
+    # with PostgreSQL 9.4. Downgrade this for earlier versions of
+    # PostgreSQL. We have this default so more things Just Work.
+    if pg_version() < '9.4' and config_data['wal_level'] == 'logical':
+        config_data['wal_level'] = 'hot_standby'
+
     # If we are replicating, some settings may need to be overridden to
     # certain minimum levels.
     num_slaves = slave_count()