Increase queue_interval to less conservative values

This means spikes are less likely to cause crashes
and we watch out for continuous degradation.

Author: josevalim

lib/db_connection.ex

@@ -433,7 +433,7 @@ defmodule DBConnection do
   started, there are two relevant options to control the queue:
 
     * `:queue_target` in milliseconds, defaults to 50ms
-    * `:queue_interval` in milliseconds, defaults to 1000ms
+    * `:queue_interval` in milliseconds, defaults to 2000ms
 
   Our goal is to wait at most `:queue_target` for a connection.
   If all connections checked out during a `:queue_interval` takes

lib/db_connection/connection_pool.ex

@@ -14,7 +14,7 @@ defmodule DBConnection.ConnectionPool do
   @behaviour DBConnection.Pool
 
   @queue_target 50
-  @queue_interval 1000
+  @queue_interval 2000
   @idle_interval 1000
   @time_unit 1000