lib/caploy/templates/unicorn/unicorn.rb.erb in caploy-0.1.3 vs lib/caploy/templates/unicorn/unicorn.rb.erb in caploy-0.1.4

@@ -13,17 +13,21 @@
     # Disconnect since the database connection will not carry over
     if defined? ActiveRecord::Base
         ActiveRecord::Base.connection.disconnect!
     end
 
-    # Quit the old unicorn process
+    # This allows a new master process to incrementally
+    # phase out the old master process with SIGTTOU to avoid a
+    # thundering herd (especially in the "preload_app false" case)
+    # when doing a transparent upgrade.  The last worker spawned
+    # will then kill off the old master process with a SIGQUIT.
     old_pid = "#{server.config[:pid]}.oldbin"
-    if File.exists?(old_pid) && server.pid != old_pid
-        begin
-            Process.kill("QUIT", File.read(old_pid).to_i)
-        rescue Errno::ENOENT, Errno::ESRCH
-            # someone else did our job for us
-        end
+    if File.exists?(old_pid) && old_pid != server.pid
+      begin
+        sig = (worker.nr + 1) >= server.worker_processes ? :QUIT : :TTOU
+        Process.kill(sig, File.read(old_pid).to_i)
+      rescue Errno::ENOENT, Errno::ESRCH
+      end
     end
 end
 
 after_fork do |server, worker|
     # Start up the database connection again in the worker
\ No newline at end of file