Maximale Anzahl an Versionen

Eine Spaltenfamilie mit einer Richtlinie für die automatische Speicherbereinigung erstellen, die angibt, wie viele Versionen beibehalten werden sollen

Weitere Informationen

Eine ausführliche Dokumentation, die dieses Codebeispiel enthält, finden Sie hier:

Codebeispiel

C#

Informationen zum Installieren und Verwenden der Clientbibliothek für Bigtable finden Sie unter Bigtable-Clientbibliotheken.

// Create a column family with GC policy : most recent N versions
// where 1 = most recent version
// Initialize request argument(s).
// Define the GC policy to retain only the most recent 2 versions
GcRule maxVersionsRule = new GcRule { MaxNumVersions = 2 };

// Column family to create
ColumnFamily columnFamily = new ColumnFamily { GcRule = maxVersionsRule };

TableName tableName = new TableName(projectId, instanceId, tableId);

// Modification to create column family
ModifyColumnFamiliesRequest.Types.Modification modification = new ModifyColumnFamiliesRequest.Types.Modification
{
    Create = columnFamily,
    Id = "cf2"
};

ModifyColumnFamiliesRequest request = new ModifyColumnFamiliesRequest
{
    TableName = tableName,
    Modifications = { modification }
};
try
{
    // Make the request
    Table response = bigtableTableAdminClient.ModifyColumnFamilies(request);
    Console.WriteLine("Created column family");
}
catch (Exception ex)
{
    Console.WriteLine($"Error creating column family {ex.Message}");
}

C++

Informationen zum Installieren und Verwenden der Clientbibliothek für Bigtable finden Sie unter Bigtable-Clientbibliotheken.

namespace cbt = ::google::cloud::bigtable;
namespace cbta = ::google::cloud::bigtable_admin;
using ::google::bigtable::admin::v2::ModifyColumnFamiliesRequest;
using ::google::cloud::StatusOr;
[](cbta::BigtableTableAdminClient admin, std::string const& project_id,
   std::string const& instance_id, std::string const& table_id,
   std::string const& family_name) {
  std::string table_name = cbt::TableName(project_id, instance_id, table_id);

  ModifyColumnFamiliesRequest::Modification mod;
  mod.set_id(family_name);
  mod.mutable_create()->mutable_gc_rule()->set_max_num_versions(2);

  StatusOr<google::bigtable::admin::v2::Table> schema =
      admin.ModifyColumnFamilies(table_name, {std::move(mod)});

  if (!schema) throw std::runtime_error(schema.status().message());
  std::cout << "Schema modified to: " << schema->DebugString() << "\n";
}

Go

Informationen zum Installieren und Verwenden der Clientbibliothek für Bigtable finden Sie unter Bigtable-Clientbibliotheken.

import (
	"context"
	"fmt"
	"io"

	"cloud.google.com/go/bigtable"
)

func createFamilyGCMaxVersions(w io.Writer, projectID, instanceID string, tableName string) error {
	// projectID := "my-project-id"
	// instanceID := "my-instance-id"
	// tableName := "my-table-name"

	ctx := context.Background()

	adminClient, err := bigtable.NewAdminClient(ctx, projectID, instanceID)
	if err != nil {
		return fmt.Errorf("bigtable.NewAdminClient: %v", err)
	}
	defer adminClient.Close()

	columnFamilyName := "cf2"
	if err := adminClient.CreateColumnFamily(ctx, tableName, columnFamilyName); err != nil {
		return fmt.Errorf("CreateColumnFamily(%s): %v", columnFamilyName, err)
	}

	// Set a garbage collection policy of 2 versions.
	policy := bigtable.MaxVersionsPolicy(2)
	if err := adminClient.SetGCPolicy(ctx, tableName, columnFamilyName, policy); err != nil {
		return fmt.Errorf("SetGCPolicy(%s): %v", policy, err)
	}

	fmt.Fprintf(w, "created column family %s with policy: %v\n", columnFamilyName, policy)
	return nil
}

Java

Informationen zum Installieren und Verwenden der Clientbibliothek für Bigtable finden Sie unter Bigtable-Clientbibliotheken.

// Creates a column family with GC policy : most recent N versions
// where 1 = most recent version

// Defines the GC policy to retain only the most recent 2 versions.
VersionRule versionRule = GCRULES.maxVersions(2);

// Creates column family with given GC rule.
try {
  // ModifyColumnFamiliesRequest can be used both for adding and modifying families, here it is
  // being used to add a family
  ModifyColumnFamiliesRequest columnFamiliesRequest =
      ModifyColumnFamiliesRequest.of(tableId).addFamily(COLUMN_FAMILY_2, versionRule);
  adminClient.modifyFamilies(columnFamiliesRequest);
  System.out.println("Created column family: " + COLUMN_FAMILY_2);
} catch (AlreadyExistsException e) {
  System.err.println(
      "Failed to create column family with rule, already exists: " + e.getMessage());
}

Node.js

Informationen zum Installieren und Verwenden der Clientbibliothek für Bigtable finden Sie unter Bigtable-Clientbibliotheken.

// Create a column family with GC policy : most recent N versions
// where 1 = most recent version

// Define the GC policy to retain only the most recent 2 versions
const maxVersionsRule = {
  rule: {
    versions: 2,
  },
};

// Create a column family with given GC rule
[family] = await table.createFamily('cf2', maxVersionsRule);
console.log(`Created column family ${family.id}`);

PHP

Informationen zum Installieren und Verwenden der Clientbibliothek für Bigtable finden Sie unter Bigtable-Clientbibliotheken.

use Google\Cloud\Bigtable\Admin\V2\ModifyColumnFamiliesRequest\Modification;
use Google\Cloud\Bigtable\Admin\V2\BigtableTableAdminClient;
use Google\Cloud\Bigtable\Admin\V2\ColumnFamily;
use Google\Cloud\Bigtable\Admin\V2\GcRule;

/**
 * Create a new column family with a max versions GC rule
 *
 * @param string $projectId The Google Cloud project ID
 * @param string $instanceId The ID of the Bigtable instance where the table resides
 * @param string $tableId The ID of the table in which the rule needs to be created
 */
function create_family_gc_max_versions(
    string $projectId,
    string $instanceId,
    string $tableId
): void {
    $tableAdminClient = new BigtableTableAdminClient();

    $tableName = $tableAdminClient->tableName($projectId, $instanceId, $tableId);

    print('Creating column family cf2 with max versions GC rule...' . PHP_EOL);
    $columnFamily2 = new ColumnFamily();
    $maxVersionRule = (new GcRule())->setMaxNumVersions(2);
    $columnFamily2->setGCRule($maxVersionRule);

    $columnModification = new Modification();
    $columnModification->setId('cf2');
    $columnModification->setCreate($columnFamily2);
    $tableAdminClient->modifyColumnFamilies($tableName, [$columnModification]);

    print('Created column family cf2 with Max Versions GC Rule.' . PHP_EOL);
}

Python

Informationen zum Installieren und Verwenden der Clientbibliothek für Bigtable finden Sie unter Bigtable-Clientbibliotheken.

    print("Creating column family cf2 with max versions GC rule...")
    # Create a column family with GC policy : most recent N versions
    # where 1 = most recent version

    # Define the GC policy to retain only the most recent 2 versions
    max_versions_rule = column_family.MaxVersionsGCRule(2)

    column_family2 = table.column_family("cf2", max_versions_rule)
    column_family2.create()
    print("Created column family cf2 with Max Versions GC Rule.")

Ruby

Informationen zum Installieren und Verwenden der Clientbibliothek für Bigtable finden Sie unter Bigtable-Clientbibliotheken.

# Create a column family with GC policy : most recent N versions
# where 1 = most recent version
max_versions_rule = Google::Cloud::Bigtable::GcRule.max_versions 2
column_families = table.column_families do |cfs|
  cfs.add "cf2", gc_rule: max_versions_rule
end
family = column_families["cf2"]

Nächste Schritte

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