message: [perf_logging] Add is_cached status when chart has error
diff: @@ -259,11 +259,12 @@ export function exploreJSON(
  return dispatch(chartUpdateSucceeded(json, key));
  })
  .catch(response => {
  - const appendErrorLog = errorDetails => {
  + const appendErrorLog = (errorDetails, isCached) => {
  dispatch(
  logEvent(LOG_ACTIONS_LOAD_CHART, {
  slice_id: key,
  has_err: true,
  + is_cached: isCached,
  error_details: errorDetails,
  datasource: formData.datasource,
  start_offset: logStart,
  @@ -283,7 +284,8 @@ export function exploreJSON(
  return dispatch(chartUpdateStopped(key));
  }
  return getClientErrorObject(response).then(parsedResponse => {
  - appendErrorLog(parsedResponse.error);
  + // query is processed, but error out.
  + appendErrorLog(parsedResponse.error, parsedResponse.is_cached);
  return dispatch(chartUpdateFailed(parsedResponse, key));
  });
  });
  