anchor.diff:  %% the mechanism is very simple; when there are more than OPS_THRESHOLD
   %% operations for a given key, just perform a read, that will trigger
   %% the GC mechanism.
  --spec op_insert_gc(key(), clocksi_payload(), ets:tid(), ets:tid()) -> true.
  +-spec op_insert_gc(key(), clocksi_payload(), cache_id(), cache_id()) -> true.
   op_insert_gc(Key, DownstreamOp, OpsCache, SnapshotCache)->
       OpsDict = case ets:lookup(OpsCache, Key) of
                     []->
  
positive.code:     end.
  
  %% @doc Remove from OpsDict all operations that have committed before Threshold.
  -spec prune_ops(orddict:orddict(), commit_time())-> orddict:orddict().
  prune_ops(OpsDict, Threshold)->
      orddict:filter(fun(_Key, Value) ->
                             (belongs_to_snapshot(Threshold,(lists:last(Value))#clocksi_payload.snapshot_time)) end, OpsDict).
  
  
negative.code:          handle_coverage/4,
           handle_exit/3]).
  
  -type cache_id() :: ets:tid().
  
  -record(state, {
    partition :: partition_id(),
    ops_cache :: cache_id(),
    snapshot_cache :: cache_id()}).
  
  start_vnode(I) ->
      riak_core_vnode_master:get_vnode_pid(I, ?MODULE).
  