Mengonfigurasi waktu tunggu kustom dan percobaan ulang

Halaman ini menunjukkan cara mengganti konfigurasi waktu tunggu default dan mengonfigurasi kebijakan percobaan ulang menggunakan library klien Spanner.

Library klien menggunakan setelan kebijakan percobaan ulang dan waktu tunggu default yang ditentukan dalam file konfigurasi berikut.

• spanner_grpc_service_config.json
• spanner_admin_instance_grpc_service_config.json
• spanner_admin_database_grpc_service_config.json

Dalam file konfigurasi, waktu tunggu default untuk operasi yang memerlukan waktu singkat, seperti CreateSession, adalah 30 detik. Operasi yang lebih lama, seperti kueri atau pembacaan, memiliki waktu tunggu default 3.600 detik. Sebaiknya gunakan nilai default ini. Namun, Anda dapat menetapkan kebijakan percobaan ulang atau waktu tunggu kustom di aplikasi jika diperlukan.

Jika Anda memutuskan untuk mengubah waktu tunggu, tetapkan ke jumlah waktu sebenarnya yang dikonfigurasi untuk menunggu hasil.

Catatan: Jangan pernah menetapkan waktu tunggu yang lebih singkat dari waktu sebenarnya yang dikonfigurasi untuk menunggu. Waktu tunggu yang singkat menyebabkan aplikasi Anda mencoba ulang operasi lebih sering dari yang diperlukan.

Jangan mengonfigurasi kebijakan percobaan ulang yang lebih agresif dari default, karena terlalu banyak percobaan ulang dapat membebani backend dan membatasi permintaan Anda.

Kebijakan percobaan ulang ditentukan di setiap cuplikan, dengan karakteristik berikut:

• Durasi waktu tunggu awal, atau awal, sebelum mencoba ulang permintaan.
• Penundaan maksimum.
• Pengali yang akan digunakan dengan waktu tunggu sebelumnya untuk menghitung waktu tunggu berikutnya, hingga maksimum tercapai.
• Kumpulan kode error untuk operasi percobaan ulang.

Dalam contoh berikut, waktu tunggu 60 detik ditetapkan untuk operasi yang diberikan. Jika operasi memerlukan waktu lebih lama dari waktu tunggu ini, operasi akan gagal dengan error DEADLINE_EXCEEDED.

Jika operasi gagal dengan kode error UNAVAILABLE, misalnya, jika ada masalah jaringan sementara, operasi akan dicoba ulang. Klien menunggu selama 500 md sebelum memulai upaya percobaan ulang pertama. Jika percobaan ulang pertama gagal, klien akan menunggu selama 1,5 * 500 md = 750 md sebelum memulai percobaan ulang kedua. Penundaan percobaan ulang ini terus meningkat hingga operasi berhasil atau mencapai penundaan percobaan ulang maksimum 16 detik. Operasi akan gagal dengan error DEADLINE_EXCEEDED jika total waktu yang dihabiskan untuk mencoba operasi melebihi nilai waktu tunggu total 60 detik.

C++

namespace spanner = ::google::cloud::spanner;
using ::google::cloud::StatusOr;
[](std::string const& project_id, std::string const& instance_id,
   std::string const& database_id) {
  // Use a truncated exponential backoff with jitter to wait between
  // retries:
  //   https://en.wikipedia.org/wiki/Exponential_backoff
  //   https://cloud.google.com/storage/docs/exponential-backoff
  auto client = spanner::Client(spanner::MakeConnection(
      spanner::Database(project_id, instance_id, database_id),
      google::cloud::Options{}
          .set<spanner::SpannerRetryPolicyOption>(
              std::make_shared<spanner::LimitedTimeRetryPolicy>(
                  /*maximum_duration=*/std::chrono::seconds(60)))
          .set<spanner::SpannerBackoffPolicyOption>(
              std::make_shared<spanner::ExponentialBackoffPolicy>(
                  /*initial_delay=*/std::chrono::milliseconds(500),
                  /*maximum_delay=*/std::chrono::seconds(16),
                  /*scaling=*/1.5))));

  std::int64_t rows_inserted;
  auto commit_result = client.Commit(
      [&client, &rows_inserted](
          spanner::Transaction txn) -> StatusOr<spanner::Mutations> {
        auto insert = client.ExecuteDml(
            std::move(txn),
            spanner::SqlStatement(
                "INSERT INTO Singers (SingerId, FirstName, LastName)"
                "  VALUES (20, 'George', 'Washington')"));
        if (!insert) return std::move(insert).status();
        rows_inserted = insert->RowsModified();
        return spanner::Mutations{};
      });
  if (!commit_result) throw std::move(commit_result).status();
  std::cout << "Rows inserted: " << rows_inserted;
}

C#

using Google.Api.Gax;
using Google.Api.Gax.Grpc;
using Google.Cloud.Spanner.Common.V1;
using Google.Cloud.Spanner.V1;
using Grpc.Core;
using System;
using System.Threading;
using System.Threading.Tasks;
using static Google.Cloud.Spanner.V1.TransactionOptions.Types;

public class CustomTimeoutsAndRetriesAsyncSample
{
    public async Task<long> CustomTimeoutsAndRetriesAsync(string projectId, string instanceId, string databaseId)
    {
        // Create a SessionPool.
        SpannerClient client = SpannerClient.Create();
        SessionPool sessionPool = new SessionPool(client, new SessionPoolOptions());

        // Acquire a session with a read-write transaction to run a query.
        DatabaseName databaseName =
            DatabaseName.FromProjectInstanceDatabase(projectId, instanceId, databaseId);
        TransactionOptions transactionOptions = new TransactionOptions
        {
            ReadWrite = new ReadWrite()
        };
        using PooledSession session = await sessionPool.AcquireSessionAsync(
            databaseName, transactionOptions, CancellationToken.None);

        ExecuteSqlRequest request = new ExecuteSqlRequest
        {
            Sql = "INSERT Singers (SingerId, FirstName, LastName) VALUES (20, 'George', 'Washington')"
        };

        // Prepare the call settings with custom timeout and retry settings.
        CallSettings settings = CallSettings
            .FromExpiration(Expiration.FromTimeout(TimeSpan.FromSeconds(60)))
            .WithRetry(RetrySettings.FromExponentialBackoff(
                maxAttempts: 12,
                initialBackoff: TimeSpan.FromMilliseconds(500),
                maxBackoff: TimeSpan.FromSeconds(16),
                backoffMultiplier: 1.5,
                retryFilter: RetrySettings.FilterForStatusCodes(
                    new StatusCode[] { StatusCode.Unavailable })));

        ResultSet result = await session.ExecuteSqlAsync(request, settings);
        await session.CommitAsync(new CommitRequest(), null);

        return result.Stats.RowCountExact;
    }
}

Go

import (
	"context"
	"fmt"
	"io"
	"time"

	"cloud.google.com/go/spanner"
	spapi "cloud.google.com/go/spanner/apiv1"
	gax "github.com/googleapis/gax-go/v2"
	"google.golang.org/grpc/codes"
)

func setCustomTimeoutAndRetry(w io.Writer, db string) error {
	// Set a custom retry setting.
	co := &spapi.CallOptions{
		ExecuteSql: []gax.CallOption{
			gax.WithRetry(func() gax.Retryer {
				return gax.OnCodes([]codes.Code{
					codes.Unavailable,
				}, gax.Backoff{
					Initial:    500 * time.Millisecond,
					Max:        16000 * time.Millisecond,
					Multiplier: 1.5,
				})
			}),
		},
	}
	client, err := spanner.NewClientWithConfig(context.Background(), db, spanner.ClientConfig{CallOptions: co})
	if err != nil {
		return err
	}
	defer client.Close()

	// Set timeout to 60s.
	ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
	defer cancel()

	_, err = client.ReadWriteTransaction(ctx, func(ctx context.Context, txn *spanner.ReadWriteTransaction) error {
		stmt := spanner.Statement{
			SQL: `INSERT Singers (SingerId, FirstName, LastName)
					VALUES (20, 'George', 'Washington')`,
		}

		rowCount, err := txn.Update(ctx, stmt)
		if err != nil {
			return err
		}
		fmt.Fprintf(w, "%d record(s) inserted.\n", rowCount)
		return nil
	})
	return err
}

Java

import com.google.api.gax.retrying.RetrySettings;
import com.google.api.gax.rpc.StatusCode.Code;
import com.google.cloud.spanner.DatabaseClient;
import com.google.cloud.spanner.DatabaseId;
import com.google.cloud.spanner.Spanner;
import com.google.cloud.spanner.SpannerOptions;
import com.google.cloud.spanner.Statement;
import org.threeten.bp.Duration;

class CustomTimeoutAndRetrySettingsExample {

  static void executeSqlWithCustomTimeoutAndRetrySettings() {
    // TODO(developer): Replace these variables before running the sample.
    String projectId = "my-project";
    String instanceId = "my-instance";
    String databaseId = "my-database";

    executeSqlWithCustomTimeoutAndRetrySettings(projectId, instanceId, databaseId);
  }

  // Create a Spanner client with custom ExecuteSql timeout and retry settings.
  static void executeSqlWithCustomTimeoutAndRetrySettings(
      String projectId, String instanceId, String databaseId) {
    SpannerOptions.Builder builder = SpannerOptions.newBuilder().setProjectId(projectId);
    // Set custom timeout and retry settings for the ExecuteSql RPC.
    // This must be done in a separate chain as the setRetryableCodes and setRetrySettings methods
    // return a UnaryCallSettings.Builder instead of a SpannerOptions.Builder.
    builder
        .getSpannerStubSettingsBuilder()
        .executeSqlSettings()
        // Configure which errors should be retried.
        .setRetryableCodes(Code.UNAVAILABLE)
        .setRetrySettings(
            RetrySettings.newBuilder()
                // Configure retry delay settings.
                // The initial amount of time to wait before retrying the request.
                .setInitialRetryDelay(Duration.ofMillis(500))
                // The maximum amount of time to wait before retrying. I.e. after this value is
                // reached, the wait time will not increase further by the multiplier.
                .setMaxRetryDelay(Duration.ofSeconds(16))
                // The previous wait time is multiplied by this multiplier to come up with the next
                // wait time, until the max is reached.
                .setRetryDelayMultiplier(1.5)

                // Configure RPC and total timeout settings.
                // Timeout for the first RPC call. Subsequent retries will be based off this value.
                .setInitialRpcTimeout(Duration.ofSeconds(60))
                // The max for the per RPC timeout.
                .setMaxRpcTimeout(Duration.ofSeconds(60))
                // Controls the change of timeout for each retry.
                .setRpcTimeoutMultiplier(1.0)
                // The timeout for all calls (first call + all retries).
                .setTotalTimeout(Duration.ofSeconds(60))
                .build());
    // Create a Spanner client using the custom retry and timeout settings.
    try (Spanner spanner = builder.build().getService()) {
      DatabaseClient client =
          spanner.getDatabaseClient(DatabaseId.of(projectId, instanceId, databaseId));
      client
          .readWriteTransaction()
          .run(transaction -> {
            String sql =
                "INSERT INTO Singers (SingerId, FirstName, LastName)\n"
                    + "VALUES (20, 'George', 'Washington')";
            long rowCount = transaction.executeUpdate(Statement.of(sql));
            System.out.printf("%d record inserted.%n", rowCount);
            return null;
          });
    }
  }
}

Node.js

// Imports the Google Cloud client library
const {Spanner} = require('@google-cloud/spanner');

/**
 * TODO(developer): Uncomment the following lines before running the sample.
 */
// const projectId = 'my-project-id';
// const instanceId = 'my-instance';
// const databaseId = 'my-database';

// Creates a client
const spanner = new Spanner({
  projectId: projectId,
});
const UNAVAILABLE_STATUS_CODE = 14;
const retryAndTimeoutSettings = {
  retry: {
    // The set of error codes that will be retried.
    retryCodes: [UNAVAILABLE_STATUS_CODE],
    backoffSettings: {
      // Configure retry delay settings.
      // The initial amount of time to wait before retrying the request.
      initialRetryDelayMillis: 500,
      // The maximum amount of time to wait before retrying. I.e. after this
      // value is reached, the wait time will not increase further by the
      // multiplier.
      maxRetryDelayMillis: 16000,
      // The previous wait time is multiplied by this multiplier to come up
      // with the next wait time, until the max is reached.
      retryDelayMultiplier: 1.5,

      // Configure RPC and total timeout settings.
      // Timeout for the first RPC call. Subsequent retries will be based off
      // this value.
      initialRpcTimeoutMillis: 60000,
      // Controls the change of timeout for each retry.
      rpcTimeoutMultiplier: 1.0,
      // The max for the per RPC timeout.
      maxRpcTimeoutMillis: 60000,
      // The timeout for all calls (first call + all retries).
      totalTimeoutMillis: 60000,
    },
  },
};

// Gets a reference to a Cloud Spanner instance and database
const instance = spanner.instance(instanceId);
const database = instance.database(databaseId);
const table = database.table('Singers');

const row = {
  SingerId: 16,
  FirstName: 'Martha',
  LastName: 'Waller',
};

await table.insert(row, retryAndTimeoutSettings);

console.log('record inserted.');

Python

from google.api_core import exceptions as core_exceptions
from google.api_core import retry

# instance_id = "your-spanner-instance"
# database_id = "your-spanner-db-id"
spanner_client = spanner.Client()
instance = spanner_client.instance(instance_id)
database = instance.database(database_id)

retry = retry.Retry(
    # Customize retry with an initial wait time of 500 milliseconds.
    initial=0.5,
    # Customize retry with a maximum wait time of 16 seconds.
    maximum=16,
    # Customize retry with a wait time multiplier per iteration of 1.5.
    multiplier=1.5,
    # Customize retry with a timeout on
    # how long a certain RPC may be retried in
    # case the server returns an error.
    timeout=60,
    # Configure which errors should be retried.
    predicate=retry.if_exception_type(
        core_exceptions.ServiceUnavailable,
    ),
)

# Set a custom retry and timeout setting.
with database.snapshot() as snapshot:
    results = snapshot.execute_sql(
        "SELECT SingerId, AlbumId, AlbumTitle FROM Albums",
        # Set custom retry setting for this request
        retry=retry,
        # Set custom timeout of 60 seconds for this request
        timeout=60,
    )

    for row in results:
        print("SingerId: {}, AlbumId: {}, AlbumTitle: {}".format(*row))

Ruby

# project_id  = "Your Google Cloud project ID"
# instance_id = "Your Spanner instance ID"
# database_id = "Your Spanner database ID"

require "google/cloud/spanner"

spanner   = Google::Cloud::Spanner.new project: project_id
client    = spanner.client instance_id, database_id
row_count = 0

timeout = 60.0
retry_policy = {
  initial_delay: 0.5,
  max_delay:     16.0,
  multiplier:    1.5,
  retry_codes:   ["UNAVAILABLE"]
}
call_options = { timeout: timeout, retry_policy: retry_policy }

client.transaction do |transaction|
  row_count = transaction.execute_update(
    "INSERT INTO Singers (SingerId, FirstName, LastName) VALUES (10, 'Virginia', 'Watson')",
    call_options: call_options
  )
end

puts "#{row_count} record inserted."