Redmine

When having a project with ~100 members (many of them are reporters) Redmine slows down and new issue and show issue takes up to 6 seconds to load. This seems to be due to that each and every Principal is queried one by one, see log below. I have tried to work out where these queries come from but have not succeeded so far. Any ideas?

  SQL (320.6ms)  SELECT `members`.`id` AS t0_r0, `members`.`user_id` AS t0_r1, `members`.`project_id` AS t0_r2, `members`.`created_on` AS t0_r3, `members`.`mail_notification` AS t0_r4, `users`.`id` AS t1_r0, `users`.`login` AS t1_r1, `users`.`hashed_password` AS t1_r2, `users`.`firstname` AS t1_r3, `users`.`lastname` AS t1_r4, `users`.`mail` AS t1_r5, `users`.`admin` AS t1_r6, `users`.`status` AS t1_r7, `users`.`last_login_on` AS t1_r8, `users`.`language` AS t1_r9, `users`.`auth_source_id` AS t1_r10, `users`.`created_on` AS t1_r11, `users`.`updated_on` AS t1_r12, `users`.`type` AS t1_r13, `users`.`identity_url` AS t1_r14, `users`.`mail_notification` AS t1_r15, `users`.`salt` AS t1_r16, `roles`.`id` AS t2_r0, `roles`.`name` AS t2_r1, `roles`.`position` AS t2_r2, `roles`.`assignable` AS t2_r3, `roles`.`builtin` AS t2_r4, `roles`.`permissions` AS t2_r5, `roles`.`issues_visibility` AS t2_r6 FROM `members` LEFT OUTER JOIN `users` ON `users`.`id` = `members`.`user_id` AND `users`.`type` IN ('User', 'AnonymousUser') LEFT OUTER JOIN `member_roles` ON `member_roles`.`member_id` = `members`.`id` LEFT OUTER JOIN `roles` ON `roles`.`id` = `member_roles`.`role_id` WHERE `members`.`project_id` = 234 AND (users.type='User' AND users.status=1)
  Principal Load (1.2ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 3 LIMIT 1
  Principal Load (1.4ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 6 LIMIT 1
  Principal Load (1.2ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 10 LIMIT 1
  Principal Load (1.2ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 11 LIMIT 1
  Principal Load (1.5ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 13 LIMIT 1
  Principal Load (0.8ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 14 LIMIT 1
  Principal Load (1.3ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 15 LIMIT 1
  Principal Load (0.8ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 17 LIMIT 1
  Principal Load (0.8ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 24 LIMIT 1
  Principal Load (1.4ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 25 LIMIT 1
  Principal Load (1.4ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 26 LIMIT 1
  Principal Load (1.2ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 29 LIMIT 1
  Principal Load (1.7ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 30 LIMIT 1
  Principal Load (3.1ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 32 LIMIT 1
  Principal Load (1.6ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 34 LIMIT 1
  Principal Load (2.0ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 35 LIMIT 1
  Principal Load (1.6ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 38 LIMIT 1
  Principal Load (2.0ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 42 LIMIT 1
  Principal Load (2.3ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 47 LIMIT 1
  Principal Load (316.4ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 49 LIMIT 1
  Principal Load (1.2ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 52 LIMIT 1
  Principal Load (1.3ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 54 LIMIT 1
  Principal Load (2.1ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 57 LIMIT 1
  Principal Load (1.1ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 60 LIMIT 1
  Principal Load (0.8ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 64 LIMIT 1
  Principal Load (0.7ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 67 LIMIT 1
  Principal Load (0.9ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 68 LIMIT 1
  ...

Ruby/Rails information:

About your application's environment
Ruby version              1.8.7 (x86_64-linux)
RubyGems version          1.4.2
Rack version              1.4
Rails version             3.2.6
Active Record version     3.2.6
Action Pack version       3.2.6
Active Resource version   3.2.6
Action Mailer version     3.2.6
Active Support version    3.2.6
Middleware                Rack::Cache, ActionDispatch::Static, Rack::Lock, #<ActiveSupport::Cache::Strategy::LocalCache::Middlewa0x7ff2d68f84e8>, Rack::Runtime, Rack::MethodOverride, ActionDispatch::RequestId, Rails::Rack::Logger, ActionDispatch::ShowExcepti, ActionDispatch::DebugExceptions, ActionDispatch::RemoteIp, ActionDispatch::Callbacks, ActiveRecord::ConnectionAdapters::ConnectManagement, ActiveRecord::QueryCache, ActionDispatch::Cookies, ActionDispatch::Session::CookieStore, ActionDispatch::Flash, Actiospatch::ParamsParser, ActionDispatch::Head, Rack::ConditionalGet, Rack::ETag, ActionDispatch::BestStandardsSupport, OpenIdAuthenttion
Application root          /opt/redmine/releases/upgrade-2.0.3
Environment               production
Database adapter          mysql
Database schema version   20120422150750

Database: mysql Ver 14.14 Distrib 5.1.52, for redhat-linux-gnu (x86_64) using readline 5.1