anchor.diff:  designator for a function of one argument to serialize lisp objects to
   JSON strings.  Returns ID on success, NIL if there was no such ID
   found."
  -  (log:debug "Attempt update of ~A in ~A" id model)
  +  (log:debu3 "Attempt update of ~A in ~A" id model)
     (ensure-model-query model 'insert-old$ 'update$)
     (with-retry-serialization-failure ("update")
       (ensure-transaction-type (update repeatable-read-rw)
  
positive.code: (defun keys (model)
    "Returns two values: a list of all primary keys for this MODEL, a
  symbol, and the length of that list."
    (ensure-model-query model 'keys$)
    (ensure-transaction-type (keys read-committed-ro)
      (keys$ model)))
  
  (defun count (model)
    "Returns the number of entries in MODEL, a symbol."
    (ensure-model-query model 'count$)
    (ensure-transaction-type (count read-committed-ro)
      (nth-value 0 (count$ model))))
  
negative.code:   "Delete the object with primary key ID (of type compatible with
  Postgres type *ID-TYPE*).  Returns ID on success, NIL if there was no
  such ID found."
    (log:debu3 "Attempt delete of object with key ~A from ~A" id model)
    (ensure-model-query model 'insert-old$ 'delete$)
    (with-retry-serialization-failure ("delete")
      (ensure-transaction-type (delete repeatable-read-rw)
  