Union garbage-collection policy

Create a column family that has a union garbage-collection policy (age and versions).

Explore further

For detailed documentation that includes this code sample, see the following:

• Configure garbage collection

Code sample

C++

To learn how to install and use the client library for Bigtable, see Bigtable client libraries.

To authenticate to Bigtable, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

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);
  auto constexpr kSecondsPerDay =
      std::chrono::seconds(std::chrono::hours(24)).count();

  ModifyColumnFamiliesRequest::Modification mod;
  mod.set_id(family_name);
  auto& gc_union = *mod.mutable_create()->mutable_gc_rule()->mutable_union_();
  gc_union.add_rules()->set_max_num_versions(1);
  gc_union.add_rules()->mutable_max_age()->set_seconds(5 * kSecondsPerDay);

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

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

C#

To learn how to install and use the client library for Bigtable, see Bigtable client libraries.

To authenticate to Bigtable, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

// Create a column family with GC policy to drop data that matches at least one condition.
// Initialize request argument(s).
// Define a GC rule to drop cells older than 5 days or not the most recent version.
GcRule.Types.Union unionRule = new GcRule.Types.Union
{
    Rules =
    {
        new GcRule { MaxNumVersions = 1 },
        new GcRule { MaxAge = Duration.FromTimeSpan(TimeSpan.FromDays(5)) }
    }
};
GcRule gcRule = new GcRule { Union = unionRule };

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

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

// Modification to create column family
ModifyColumnFamiliesRequest.Types.Modification modification = new ModifyColumnFamiliesRequest.Types.Modification
{
    Create = columnFamily,
    Id = "cf3"
};

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}");
}

Go

To learn how to install and use the client library for Bigtable, see Bigtable client libraries.

To authenticate to Bigtable, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

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

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

func createFamilyGCUnion(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: %w", err)
	}
	defer adminClient.Close()

	columnFamilyName := "cf3"
	if err := adminClient.CreateColumnFamily(ctx, tableName, columnFamilyName); err != nil {
		return fmt.Errorf("CreateColumnFamily(%s): %w", columnFamilyName, err)
	}

	// Define a GC rule to drop cells older than 5 days or not the most recent version
	maxAge := time.Hour * 24 * 5
	maxAgePolicy := bigtable.MaxAgePolicy(maxAge)
	policy := bigtable.UnionPolicy(bigtable.MaxVersionsPolicy(2), maxAgePolicy)
	if err := adminClient.SetGCPolicy(ctx, tableName, columnFamilyName, policy); err != nil {
		return fmt.Errorf("SetGCPolicy(%s): %w", policy, err)
	}

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

Java

To learn how to install and use the client library for Bigtable, see Bigtable client libraries.

To authenticate to Bigtable, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

// Creates a column family with GC policy to drop data that matches at least one condition.

// Defines a list of GC rules to drop cells older than 5 days OR not the most recent
// version.
UnionRule unionRule =
    GCRULES.union().rule(GCRULES.maxAge(5, TimeUnit.DAYS)).rule(GCRULES.maxVersions(1));

// 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_3, unionRule);
  adminClient.modifyFamilies(columnFamiliesRequest);
  System.out.println("Created column family: " + COLUMN_FAMILY_3);
} catch (AlreadyExistsException e) {
  System.err.println(
      "Failed to create column family with rule, already exists: " + e.getMessage());
}

Node.js

To learn how to install and use the client library for Bigtable, see Bigtable client libraries.

To authenticate to Bigtable, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

// Create a column family with GC policy to drop data that matches at least one condition.

// Define a GC rule to drop cells older than 5 days or not the most recent version
const unionRule = {
  rule: {
    versions: 1,
    age: {
      seconds: 60 * 60 * 24 * 5,
      nanos: 0,
    },
    union: true,
  },
};

[family] = await table.createFamily('cf3', unionRule);
console.log(`Created column family ${family.id}`);

PHP

To learn how to install and use the client library for Bigtable, see Bigtable client libraries.

To authenticate to Bigtable, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

use Google\Cloud\Bigtable\Admin\V2\Client\BigtableTableAdminClient;
use Google\Cloud\Bigtable\Admin\V2\ColumnFamily;
use Google\Cloud\Bigtable\Admin\V2\GcRule;
use Google\Cloud\Bigtable\Admin\V2\GcRule\Union as GcRuleUnion;
use Google\Cloud\Bigtable\Admin\V2\ModifyColumnFamiliesRequest;
use Google\Cloud\Bigtable\Admin\V2\ModifyColumnFamiliesRequest\Modification;
use Google\Protobuf\Duration;

/**
 * Create a new column family with a union 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_union(
    string $projectId,
    string $instanceId,
    string $tableId
): void {
    $tableAdminClient = new BigtableTableAdminClient();

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

    print('Creating column family cf3 with union GC rule...' . PHP_EOL);
    // Create a column family with GC policy to drop data that matches
    // at least one condition.
    // Define a GC rule to drop cells older than 5 days or not the
    // most recent version

    $columnFamily3 = new ColumnFamily();

    $ruleUnion = new GcRuleUnion();
    $ruleUnionArray = [
        (new GcRule())->setMaxNumVersions(2),
        (new GcRule())->setMaxAge((new Duration())->setSeconds(3600 * 24 * 5))
    ];
    $ruleUnion->setRules($ruleUnionArray);
    $union = new GcRule();
    $union->setUnion($ruleUnion);

    $columnFamily3->setGCRule($union);

    $columnModification = new Modification();
    $columnModification->setId('cf3');
    $columnModification->setCreate($columnFamily3);
    $modifyColumnFamiliesRequest = (new ModifyColumnFamiliesRequest())
        ->setName($tableName)
        ->setModifications([$columnModification]);
    $tableAdminClient->modifyColumnFamilies($modifyColumnFamiliesRequest);

    print('Created column family cf3 with Union GC rule.' . PHP_EOL);
}

Python

To learn how to install and use the client library for Bigtable, see Bigtable client libraries.

To authenticate to Bigtable, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

    print("Creating column family cf3 with union GC rule...")
    # Create a column family with GC policy to drop data that matches
    # at least one condition.
    # Define a GC rule to drop cells older than 5 days or not the
    # most recent version
    union_rule = column_family.GCRuleUnion(
        [
            column_family.MaxAgeGCRule(datetime.timedelta(days=5)),
            column_family.MaxVersionsGCRule(2),
        ]
    )

    column_family3 = table.column_family("cf3", union_rule)
    column_family3.create()
    print("Created column family cf3 with Union GC rule")

Ruby

To learn how to install and use the client library for Bigtable, see Bigtable client libraries.

To authenticate to Bigtable, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

# Create a column family with GC policy to drop data that matches at least
# one condition
max_age_rule = Google::Cloud::Bigtable::GcRule.max_age 60 * 60 * 24 * 5
max_versions_rule = Google::Cloud::Bigtable::GcRule.max_versions 2
union_gc_rule = Google::Cloud::Bigtable::GcRule.union max_age_rule, max_versions_rule
column_families = table.column_families do |cfs|
  cfs.add "cf3", gc_rule: union_gc_rule
end
family = column_families["cf3"]

What's next

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