anchor.diff:  
   |===
   
  +Metrics has some special support for stream-based alerting, see <<Metrics Group Triggers>> for the details.
  +
   
   === Query-Based Alerting
   Whereas stream-based alerting is applied to metric data as it arrives, it is often the case that issues
  
positive.code:   frequency      duration string (see below), time between query-executions/evals
    eval           string, expression determining condition match
    evalType       string, one of [ALL (default), EACH]. See more below.
   
   
  Query
  
negative.code: A note about using *EACH*.  If multiple queries are involved in the eval expression then that only metrics common to each query will be evaluated.  For example, if the eval above were `q(qNow,avg) >  q(qYesterday,avg)` and only M1 were common to both queries then the eval would only be resolved using M1 data points.  In general each query will likely use the same metrics so this issue is a corner case.
  
  The default is ALL.
  
  ===== QuietCount
  Setting `ConditionExpression.evalType=EACH` means the expression is evaluated for each metric targeted by the query. It allows one trigger definition to apply to many different metrics, which can be powerful. But the downside is that using trigger options like autoDisable or AutoResolve becomes difficult. If the trigger fires because of metric A, and then disables, it may miss issues fo metric B.  Autoresolve has the same problem, it is hard to apply due to the variety of metrics that may have fired the trigger.
  
  Although not a replacement for the options mentioned above, setting `ConditionExpression.quietCount` can be useful. If set > 0 it suppresses redundant firing for the same metric until that metric has returned to a steady state.  Put another way, if set to N it means: after the trigger fired metric A, stay quiet (no firing for A) until after we see N false evaluations for metric A.  The count is tracked independently per metric, so a firing for metric A does not affect metric B.
  
  ===== Metrics and Tags
  The `Query.metrics` and `Query.tags` fields are used to specify the metrics involved in the query, and therefore the data being retrieved. One of the fields must be specified. They are mutually exclusive, so specifying both is an error.  
  