[server] Make connection pooler configurable and set better default values Drop the configuration connections-pool-size and add new configurations options: * connections-pool-min-size. Set to 0 by default so we open connections only when needed. This avoid opening min-size*processes connections at startup, which is, it think, a good default. * connections-pool-max-size. Set to 0 (unlimited) by default, so we move the bottleneck to postgresql. * connections-idle-timeout. Set to 10 minutes. I don't have arguments about this except that this is the default in pgbouncer.

import ConfigParser
try:
    undo_actions = config.cfgfile_parser.get('MAIN', 'undo-support', False)
except ConfigParser.NoOptionError:
    pass # this conf. file was probably already migrated
else:
    config.global_set_option('undo-enabled', bool(undo_actions))