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// to you under the Apache License, Version 2.0 (the
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//
//   http://www.apache.org/licenses/LICENSE-2.0
//
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#include "util/metrics.h"

namespace impala {

/// class which is used to refresh the metastore event related metrics from catalog
class MetastoreEventMetrics {
 public:
  /// Registers and initializes the Metastore event metrics
  static void InitMetastoreEventMetrics(MetricGroup* metric_group);

  /// refresh all the metrics which are used to display on webui based on the given
  /// response this method should be called at regular intervals to update the metrics
  /// information on the webui
  static void refresh(TEventProcessorMetrics* response);

  /// Total number of events received so far
  static IntCounter* NUM_EVENTS_RECEIVED_COUNTER;

  /// Total number of events skipped so far
  static IntCounter* NUM_EVENTS_SKIPPED_COUNTER;

  /// Mean duration required to fetch a batch of events
  static DoubleGauge* EVENTS_FETCH_DURATION_MEAN;

  /// Mean duration required to process the fetched batch of events
  static DoubleGauge* EVENTS_PROCESS_DURATION_MEAN;

  /// The current status of Metastore events processor.
  /// See MetastoreEventProcessor.EventProcessorStatus for possible state values
  static StringProperty* EVENT_PROCESSOR_STATUS;

  /// Exponentially weighted moving avg (EWMA) of number of events received in last 1 min
  static DoubleGauge* EVENTS_RECEIVED_1MIN_RATE;

  /// EWMA of number of events received in last 5 min
  static DoubleGauge* EVENTS_RECEIVED_5MIN_RATE;

  /// EWMA of number of events received in last 15 min
  static DoubleGauge* EVENTS_RECEIVED_15MIN_RATE;

  /// Last metastore event id that the catalog server synced to.
  static IntCounter* LAST_SYNCED_EVENT_ID;

 private:
  /// Following metric names must match with the key in metrics.json

  /// metric name for events received counter.
  static string NUMBER_EVENTS_RECEIVED_METRIC_NAME;

  /// metric name for events skipped counter
  static string NUMBER_EVENTS_SKIPPED_METRIC_NAME;

  /// metric name for event processor status
  static string EVENT_PROCESSOR_STATUS_METRIC_NAME;

  /// metric name for the mean time taken for events fetch metric
  static string EVENTS_FETCH_DURATION_MEAN_METRIC_NAME;

  /// metric name for the mean time taken for events processing metric
  static string EVENTS_PROCESS_DURATION_MEAN_METRIC_NAME;

  /// metric name for EWMA of number of events in last 1 min
  static string EVENTS_RECEIVED_1MIN_METRIC_NAME;

  /// metric name for EWMA of number of events in last 5 min
  static string EVENTS_RECEIVED_5MIN_METRIC_NAME;

  /// metric name for EWMA of number of events in last 15 min
  static string EVENTS_RECEIVED_15MIN_METRIC_NAME;

  /// Metric name for last metastore event id that the catalog server synced to.
  static string LAST_SYNCED_EVENT_ID_METRIC_NAME;
};

} // namespace impala