extend('PagerDefault') doesn't call pager_default_initialize
As documented on the See the Extenders page on drupal.org:


  To use an extender, you must first have a query object. From the query object, the extend() method will return a new object that should be used in place of the query object. For example:


$query = $query-&gt;extend('PagerDefault');



  The above line takes a select query, creates a new PagerDefault query object that contains the original select query, and returns the new object. $query may now be used as if it were the original query object but with additional methods now available.
  
  Note that $query is not altered in place. The new object is returned from extend(), and if it is not saved to a variable it will be lost. For example, the following will not do what you expect:


So, you first line should looks like:

$query = db_select('redagavimas', 'r')-&gt;extend('PagerDefault')-&gt;fields("r");