// Copyright 2022 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

syntax = "proto3";

package google.bigtable.v2;

import "google/protobuf/duration.proto";

option csharp_namespace = "Google.Cloud.Bigtable.V2";
option go_package = "google.golang.org/genproto/googleapis/bigtable/v2;bigtable";
option java_multiple_files = true;
option java_outer_classname = "RequestStatsProto";
option java_package = "com.google.bigtable.v2";
option php_namespace = "Google\\Cloud\\Bigtable\\V2";
option ruby_package = "Google::Cloud::Bigtable::V2";

//
// Messages related to RequestStats, part of the Query Stats feature, that can
// help understand the performance of requests.
//
// The layout of requests below is as follows:
//   * RequestStats serves as the top-level container for statistics and
//     measures related to Bigtable requests. This common object is returned as
//     part of methods in the Data API.
//   * RequestStats contains multiple *views* of related data, chosen by an
//     option in the source Data API method. The view that is returned is
//     designed to have all submessages (and their submessages, and so on)
//     filled-in, to provide a comprehensive selection of statistics and
//     measures related to the requested view.

// ReadIterationStats captures information about the iteration of rows or cells
// over the course of a read, e.g. how many results were scanned in a read
// operation versus the results returned.
message ReadIterationStats {
  // The rows seen (scanned) as part of the request. This includes the count of
  // rows returned, as captured below.
  int64 rows_seen_count = 1;

  // The rows returned as part of the request.
  int64 rows_returned_count = 2;

  // The cells seen (scanned) as part of the request. This includes the count of
  // cells returned, as captured below.
  int64 cells_seen_count = 3;

  // The cells returned as part of the request.
  int64 cells_returned_count = 4;
}

// RequestLatencyStats provides a measurement of the latency of the request as
// it interacts with different systems over its lifetime, e.g. how long the
// request took to execute within a frontend server.
message RequestLatencyStats {
  // The latency measured by the frontend server handling this request, from
  // when the request was received, to when this value is sent back in the
  // response. For more context on the component that is measuring this latency,
  // see: https://cloud.google.com/bigtable/docs/overview
  //
  // Note: This value may be slightly shorter than the value reported into
  // aggregate latency metrics in Monitoring for this request
  // (https://cloud.google.com/bigtable/docs/monitoring-instance) as this value
  // needs to be sent in the response before the latency measurement including
  // that transmission is finalized.
  //
  // Note: This value includes the end-to-end latency of contacting nodes in
  // the targeted cluster, e.g. measuring from when the first byte arrives at
  // the frontend server, to when this value is sent back as the last value in
  // the response, including any latency incurred by contacting nodes, waiting
  // for results from nodes, and finally sending results from nodes back to the
  // caller.
  google.protobuf.Duration frontend_server_latency = 1;
}

// FullReadStatsView captures all known information about a read.
message FullReadStatsView {
  // Iteration stats describe how efficient the read is, e.g. comparing
  // rows seen vs. rows returned or cells seen vs cells returned can provide an
  // indication of read efficiency (the higher the ratio of seen to retuned the
  // better).
  ReadIterationStats read_iteration_stats = 1;

  // Request latency stats describe the time taken to complete a request, from
  // the server side.
  RequestLatencyStats request_latency_stats = 2;
}

// RequestStats is the container for additional information pertaining to a
// single request, helpful for evaluating the performance of the sent request.
// Currently, there are the following supported methods:
//   * google.bigtable.v2.ReadRows
message RequestStats {
  // Information pertaining to each request type received. The type is chosen
  // based on the requested view.
  //
  // See the messages above for additional context.
  oneof stats_view {
    // Available with the ReadRowsRequest.RequestStatsView.REQUEST_STATS_FULL
    // view, see package google.bigtable.v2.
    FullReadStatsView full_read_stats_view = 1;
  }
}