anchor.diff:  was used only during migration between different Google storage
   APIs. Now it is disabled on the server-side."))
   
  -(defgeneric delete-files (blobstore blob-keys)
  +(defgeneric delete-files (blobstore blob-keys &key batch-size)
     (:documentation
      "Deletes files from BLOBSTORE. The fiels
   are specified by BLOB-KEYS - a list of strings."))
  
positive.code:     "AMIfv97suboJpeei-uBWzlkqcR7CTlyh0Izhvi7u_29HNBgu80ScYf0Mj6zWPjgbsosA-F0Q12HP8o9S5zhsEelTfss8_3C7sjgcuG_q_grR-jMfXPLLRzu6CNytLoNk23rwqlQ6AsajxTRYFubFbz3iBWl5uo8iZQ"
      "AMIfv97wo4FQxGLBZOagyZyLZCqwMWavAfwsByKxjq8QiJQ5rIzEggGwGJ_kH2qRZLMb8N_el8aKIpLDbnr67Pxcy9r8RFKmBnjTQ1B44yaCcyZWtO2CSbBliyAINvoI41_R8uA8hoPia-yXPdlmADiJcavCCgpHGA"))
  
  (defmethod delete-files (blobstore blob-keys)
    (flet ((delete-batch (blob-keys)
             (multiple-value-bind (body status-code headers uri stream2 must-close reason-phrase)
                 (drakma:http-request (format nil "~A/delete-blobs" (base-url blobstore))
  
negative.code:     (let* ((filtered-keys (set-difference blob-keys *logs-to-keep* :test #'string=))
             (total (length filtered-keys))
             (done 0))
        (dolist (batch (test-grid-utils::split-list filtered-keys batch-size))
          (delete-batch batch)
          (incf done (length batch))
          (log:info "~A/~A files deleted" done total)))))
  