Erstellen Sie mit AWS SDK for Java 2.x eine regionale Tabelle, die für die MRSC-Konvertierung bereit ist.
public static CreateTableResponse createRegionalTable(final DynamoDbClient dynamoDbClient, final String tableName) {
if (dynamoDbClient == null) {
throw new IllegalArgumentException("DynamoDB client cannot be null");
}
if (tableName == null || tableName.trim().isEmpty()) {
throw new IllegalArgumentException("Table name cannot be null or empty");
}
try {
LOGGER.info("Creating regional table: " + tableName + " (must be empty for MRSC)");
CreateTableRequest createTableRequest = CreateTableRequest.builder()
.tableName(tableName)
.attributeDefinitions(
AttributeDefinition.builder()
.attributeName("Artist")
.attributeType(ScalarAttributeType.S)
.build(),
AttributeDefinition.builder()
.attributeName("SongTitle")
.attributeType(ScalarAttributeType.S)
.build())
.keySchema(
KeySchemaElement.builder()
.attributeName("Artist")
.keyType(KeyType.HASH)
.build(),
KeySchemaElement.builder()
.attributeName("SongTitle")
.keyType(KeyType.RANGE)
.build())
.billingMode(BillingMode.PAY_PER_REQUEST)
.build();
CreateTableResponse response = dynamoDbClient.createTable(createTableRequest);
LOGGER.info("Regional table creation initiated. Status: "
+ response.tableDescription().tableStatus());
return response;
} catch (DynamoDbException e) {
LOGGER.severe("Failed to create regional table: " + tableName + " - " + e.getMessage());
throw DynamoDbException.builder()
.message("Failed to create regional table: " + tableName)
.cause(e)
.build();
}
}
Konvertieren Sie mit AWS SDK for Java 2.x eine regionale Tabelle in eine MRSC-Tabelle mit Replikaten und Witnesses.
public static UpdateTableResponse convertToMRSCWithWitness(
final DynamoDbClient dynamoDbClient,
final String tableName,
final Region replicaRegion,
final Region witnessRegion) {
if (dynamoDbClient == null) {
throw new IllegalArgumentException("DynamoDB client cannot be null");
}
if (tableName == null || tableName.trim().isEmpty()) {
throw new IllegalArgumentException("Table name cannot be null or empty");
}
if (replicaRegion == null) {
throw new IllegalArgumentException("Replica region cannot be null");
}
if (witnessRegion == null) {
throw new IllegalArgumentException("Witness region cannot be null");
}
try {
LOGGER.info("Converting table to MRSC with replica in " + replicaRegion.id() + " and witness in "
+ witnessRegion.id());
// Create replica update using ReplicationGroupUpdate
ReplicationGroupUpdate replicaUpdate = ReplicationGroupUpdate.builder()
.create(CreateReplicationGroupMemberAction.builder()
.regionName(replicaRegion.id())
.build())
.build();
// Create witness update
GlobalTableWitnessGroupUpdate witnessUpdate = GlobalTableWitnessGroupUpdate.builder()
.create(CreateGlobalTableWitnessGroupMemberAction.builder()
.regionName(witnessRegion.id())
.build())
.build();
UpdateTableRequest updateTableRequest = UpdateTableRequest.builder()
.tableName(tableName)
.replicaUpdates(List.of(replicaUpdate))
.globalTableWitnessUpdates(List.of(witnessUpdate))
.multiRegionConsistency(MultiRegionConsistency.STRONG)
.build();
UpdateTableResponse response = dynamoDbClient.updateTable(updateTableRequest);
LOGGER.info("MRSC conversion initiated. Status: "
+ response.tableDescription().tableStatus());
LOGGER.info("UpdateTableResponse full object: " + response);
return response;
} catch (DynamoDbException e) {
LOGGER.severe("Failed to convert table to MRSC: " + tableName + " - " + e.getMessage());
throw DynamoDbException.builder()
.message("Failed to convert table to MRSC: " + tableName)
.cause(e)
.build();
}
}
Beschreiben Sie mit AWS SDK for Java 2.x eine globale MRSC-Tabellenkonfiguration.
public static DescribeTableResponse describeMRSCTable(final DynamoDbClient dynamoDbClient, final String tableName) {
if (dynamoDbClient == null) {
throw new IllegalArgumentException("DynamoDB client cannot be null");
}
if (tableName == null || tableName.trim().isEmpty()) {
throw new IllegalArgumentException("Table name cannot be null or empty");
}
try {
LOGGER.info("Describing MRSC global table: " + tableName);
DescribeTableRequest request =
DescribeTableRequest.builder().tableName(tableName).build();
DescribeTableResponse response = dynamoDbClient.describeTable(request);
LOGGER.info("Table status: " + response.table().tableStatus());
LOGGER.info("Multi-region consistency: " + response.table().multiRegionConsistency());
if (response.table().replicas() != null
&& !response.table().replicas().isEmpty()) {
LOGGER.info("Number of replicas: " + response.table().replicas().size());
response.table()
.replicas()
.forEach(replica -> LOGGER.info(
"Replica region: " + replica.regionName() + ", Status: " + replica.replicaStatus()));
}
if (response.table().globalTableWitnesses() != null
&& !response.table().globalTableWitnesses().isEmpty()) {
LOGGER.info("Number of witnesses: "
+ response.table().globalTableWitnesses().size());
response.table()
.globalTableWitnesses()
.forEach(witness -> LOGGER.info(
"Witness region: " + witness.regionName() + ", Status: " + witness.witnessStatus()));
}
return response;
} catch (ResourceNotFoundException e) {
LOGGER.severe("Table not found: " + tableName + " - " + e.getMessage());
throw DynamoDbException.builder()
.message("Table not found: " + tableName)
.cause(e)
.build();
} catch (DynamoDbException e) {
LOGGER.severe("Failed to describe table: " + tableName + " - " + e.getMessage());
throw DynamoDbException.builder()
.message("Failed to describe table: " + tableName)
.cause(e)
.build();
}
}
Fügen Sie mit AWS SDK for Java 2.x Testelemente hinzu, um die starke Konsistenz (MRSC) zu überprüfen.
public static PutItemResponse putTestItem(
final DynamoDbClient dynamoDbClient,
final String tableName,
final String artist,
final String songTitle,
final String album,
final String year) {
if (dynamoDbClient == null) {
throw new IllegalArgumentException("DynamoDB client cannot be null");
}
if (tableName == null || tableName.trim().isEmpty()) {
throw new IllegalArgumentException("Table name cannot be null or empty");
}
if (artist == null || artist.trim().isEmpty()) {
throw new IllegalArgumentException("Artist cannot be null or empty");
}
if (songTitle == null || songTitle.trim().isEmpty()) {
throw new IllegalArgumentException("Song title cannot be null or empty");
}
try {
LOGGER.info("Adding test item to MRSC global table: " + tableName);
Map<String, AttributeValue> item = new HashMap<>();
item.put("Artist", AttributeValue.builder().s(artist).build());
item.put("SongTitle", AttributeValue.builder().s(songTitle).build());
if (album != null && !album.trim().isEmpty()) {
item.put("Album", AttributeValue.builder().s(album).build());
}
if (year != null && !year.trim().isEmpty()) {
item.put("Year", AttributeValue.builder().n(year).build());
}
PutItemRequest putItemRequest =
PutItemRequest.builder().tableName(tableName).item(item).build();
PutItemResponse response = dynamoDbClient.putItem(putItemRequest);
LOGGER.info("Test item added successfully with strong consistency");
return response;
} catch (DynamoDbException e) {
LOGGER.severe("Failed to add test item to table: " + tableName + " - " + e.getMessage());
throw DynamoDbException.builder()
.message("Failed to add test item to table: " + tableName)
.cause(e)
.build();
}
}
Lesen Sie mit AWS SDK for Java 2.x Elemente mit konsistenten Lesevorgängen aus MRSC-Replikaten.
public static GetItemResponse getItemWithConsistentRead(
final DynamoDbClient dynamoDbClient, final String tableName, final String artist, final String songTitle) {
if (dynamoDbClient == null) {
throw new IllegalArgumentException("DynamoDB client cannot be null");
}
if (tableName == null || tableName.trim().isEmpty()) {
throw new IllegalArgumentException("Table name cannot be null or empty");
}
if (artist == null || artist.trim().isEmpty()) {
throw new IllegalArgumentException("Artist cannot be null or empty");
}
if (songTitle == null || songTitle.trim().isEmpty()) {
throw new IllegalArgumentException("Song title cannot be null or empty");
}
try {
LOGGER.info("Reading item from MRSC global table with consistent read: " + tableName);
Map<String, AttributeValue> key = new HashMap<>();
key.put("Artist", AttributeValue.builder().s(artist).build());
key.put("SongTitle", AttributeValue.builder().s(songTitle).build());
GetItemRequest getItemRequest = GetItemRequest.builder()
.tableName(tableName)
.key(key)
.consistentRead(true)
.build();
GetItemResponse response = dynamoDbClient.getItem(getItemRequest);
if (response.hasItem()) {
LOGGER.info("Item found with strong consistency - no wait time needed");
} else {
LOGGER.info("Item not found");
}
return response;
} catch (DynamoDbException e) {
LOGGER.severe("Failed to read item from table: " + tableName + " - " + e.getMessage());
throw DynamoDbException.builder()
.message("Failed to read item from table: " + tableName)
.cause(e)
.build();
}
}
Führen Sie mit AWS SDK for Java 2.x bedingte Aktualisierungen mit MRSC-Garantien durch.
public static UpdateItemResponse performConditionalUpdate(
final DynamoDbClient dynamoDbClient,
final String tableName,
final String artist,
final String songTitle,
final String rating) {
if (dynamoDbClient == null) {
throw new IllegalArgumentException("DynamoDB client cannot be null");
}
if (tableName == null || tableName.trim().isEmpty()) {
throw new IllegalArgumentException("Table name cannot be null or empty");
}
if (artist == null || artist.trim().isEmpty()) {
throw new IllegalArgumentException("Artist cannot be null or empty");
}
if (songTitle == null || songTitle.trim().isEmpty()) {
throw new IllegalArgumentException("Song title cannot be null or empty");
}
if (rating == null || rating.trim().isEmpty()) {
throw new IllegalArgumentException("Rating cannot be null or empty");
}
try {
LOGGER.info("Performing conditional update on MRSC global table: " + tableName);
Map<String, AttributeValue> key = new HashMap<>();
key.put("Artist", AttributeValue.builder().s(artist).build());
key.put("SongTitle", AttributeValue.builder().s(songTitle).build());
Map<String, String> expressionAttributeNames = new HashMap<>();
expressionAttributeNames.put("#rating", "Rating");
Map<String, AttributeValue> expressionAttributeValues = new HashMap<>();
expressionAttributeValues.put(
":rating", AttributeValue.builder().n(rating).build());
UpdateItemRequest updateItemRequest = UpdateItemRequest.builder()
.tableName(tableName)
.key(key)
.updateExpression("SET #rating = :rating")
.conditionExpression("attribute_exists(Artist)")
.expressionAttributeNames(expressionAttributeNames)
.expressionAttributeValues(expressionAttributeValues)
.build();
UpdateItemResponse response = dynamoDbClient.updateItem(updateItemRequest);
LOGGER.info("Conditional update successful - demonstrates strong consistency");
return response;
} catch (ConditionalCheckFailedException e) {
LOGGER.warning("Conditional check failed: " + e.getMessage());
throw e;
} catch (DynamoDbException e) {
LOGGER.severe("Failed to perform conditional update: " + tableName + " - " + e.getMessage());
throw DynamoDbException.builder()
.message("Failed to perform conditional update: " + tableName)
.cause(e)
.build();
}
}
Warten Sie mit AWS SDK for Java 2.x, bis MRSC-Replikate und Witnesses aktiv werden.
public static void waitForMRSCReplicasActive(
final DynamoDbClient dynamoDbClient, final String tableName, final int maxWaitTimeSeconds)
throws InterruptedException {
if (dynamoDbClient == null) {
throw new IllegalArgumentException("DynamoDB client cannot be null");
}
if (tableName == null || tableName.trim().isEmpty()) {
throw new IllegalArgumentException("Table name cannot be null or empty");
}
if (maxWaitTimeSeconds <= 0) {
throw new IllegalArgumentException("Max wait time must be positive");
}
try {
LOGGER.info("Waiting for MRSC replicas and witnesses to become active: " + tableName);
final long startTime = System.currentTimeMillis();
final long maxWaitTimeMillis = maxWaitTimeSeconds * 1000L;
int backoffSeconds = 5; // Start with 5 second intervals
final int maxBackoffSeconds = 30; // Cap at 30 seconds
while (System.currentTimeMillis() - startTime < maxWaitTimeMillis) {
DescribeTableResponse response = describeMRSCTable(dynamoDbClient, tableName);
boolean allActive = true;
StringBuilder statusReport = new StringBuilder();
if (response.table().multiRegionConsistency() == null
|| !MultiRegionConsistency.STRONG
.toString()
.equals(response.table().multiRegionConsistency().toString())) {
allActive = false;
statusReport
.append("MultiRegionConsistency: ")
.append(response.table().multiRegionConsistency())
.append(" ");
}
if (response.table().replicas() == null
|| response.table().replicas().isEmpty()) {
allActive = false;
statusReport.append("No replicas found. ");
}
if (response.table().globalTableWitnesses() == null
|| response.table().globalTableWitnesses().isEmpty()) {
allActive = false;
statusReport.append("No witnesses found. ");
}
// Check table status
if (!"ACTIVE".equals(response.table().tableStatus().toString())) {
allActive = false;
statusReport
.append("Table: ")
.append(response.table().tableStatus())
.append(" ");
}
// Check replica status
if (response.table().replicas() != null) {
for (var replica : response.table().replicas()) {
if (!"ACTIVE".equals(replica.replicaStatus().toString())) {
allActive = false;
statusReport
.append("Replica(")
.append(replica.regionName())
.append("): ")
.append(replica.replicaStatus())
.append(" ");
}
}
}
// Check witness status
if (response.table().globalTableWitnesses() != null) {
for (var witness : response.table().globalTableWitnesses()) {
if (!"ACTIVE".equals(witness.witnessStatus().toString())) {
allActive = false;
statusReport
.append("Witness(")
.append(witness.regionName())
.append("): ")
.append(witness.witnessStatus())
.append(" ");
}
}
}
if (allActive) {
LOGGER.info("All MRSC replicas and witnesses are now active: " + tableName);
return;
}
LOGGER.info("Waiting for MRSC components to become active. Status: " + statusReport.toString());
LOGGER.info("Next check in " + backoffSeconds + " seconds...");
tempWait(backoffSeconds);
// Exponential backoff with cap
backoffSeconds = Math.min(backoffSeconds * 2, maxBackoffSeconds);
}
throw DynamoDbException.builder()
.message("Timeout waiting for MRSC replicas to become active after " + maxWaitTimeSeconds + " seconds")
.build();
} catch (DynamoDbException | InterruptedException e) {
LOGGER.severe("Failed to wait for MRSC replicas to become active: " + tableName + " - " + e.getMessage());
throw e;
}
}
Bereinigen Sie mit AWS SDK for Java 2.x MRSC-Replikate und Witnesses.
public static UpdateTableResponse cleanupMRSCReplicas(
final DynamoDbClient dynamoDbClient,
final String tableName,
final Region replicaRegion,
final Region witnessRegion) {
if (dynamoDbClient == null) {
throw new IllegalArgumentException("DynamoDB client cannot be null");
}
if (tableName == null || tableName.trim().isEmpty()) {
throw new IllegalArgumentException("Table name cannot be null or empty");
}
if (replicaRegion == null) {
throw new IllegalArgumentException("Replica region cannot be null");
}
if (witnessRegion == null) {
throw new IllegalArgumentException("Witness region cannot be null");
}
try {
LOGGER.info("Cleaning up MRSC replicas and witnesses for table: " + tableName);
// Remove replica using ReplicationGroupUpdate
ReplicationGroupUpdate replicaUpdate = ReplicationGroupUpdate.builder()
.delete(DeleteReplicationGroupMemberAction.builder()
.regionName(replicaRegion.id())
.build())
.build();
// Remove witness
GlobalTableWitnessGroupUpdate witnessUpdate = GlobalTableWitnessGroupUpdate.builder()
.delete(DeleteGlobalTableWitnessGroupMemberAction.builder()
.regionName(witnessRegion.id())
.build())
.build();
UpdateTableRequest updateTableRequest = UpdateTableRequest.builder()
.tableName(tableName)
.replicaUpdates(List.of(replicaUpdate))
.globalTableWitnessUpdates(List.of(witnessUpdate))
.build();
UpdateTableResponse response = dynamoDbClient.updateTable(updateTableRequest);
LOGGER.info("MRSC cleanup initiated - removing replica and witness. Response: " + response);
return response;
} catch (DynamoDbException e) {
LOGGER.severe("Failed to cleanup MRSC replicas: " + tableName + " - " + e.getMessage());
throw DynamoDbException.builder()
.message("Failed to cleanup MRSC replicas: " + tableName)
.cause(e)
.build();
}
}
Schließen Sie die Demonstration des MRSC-Workflows mit AWS SDK for Java 2.x ab.
public static void demonstrateCompleteMRSCWorkflow(
final DynamoDbClient primaryClient,
final DynamoDbClient replicaClient,
final String tableName,
final Region replicaRegion,
final Region witnessRegion)
throws InterruptedException {
if (primaryClient == null) {
throw new IllegalArgumentException("Primary DynamoDB client cannot be null");
}
if (replicaClient == null) {
throw new IllegalArgumentException("Replica DynamoDB client cannot be null");
}
if (tableName == null || tableName.trim().isEmpty()) {
throw new IllegalArgumentException("Table name cannot be null or empty");
}
if (replicaRegion == null) {
throw new IllegalArgumentException("Replica region cannot be null");
}
if (witnessRegion == null) {
throw new IllegalArgumentException("Witness region cannot be null");
}
try {
LOGGER.info("=== Starting Complete MRSC Workflow Demonstration ===");
// Step 1: Create an empty single-Region table
LOGGER.info("Step 1: Creating empty single-Region table");
createRegionalTable(primaryClient, tableName);
// Use the existing GlobalTableOperations method for basic table waiting
LOGGER.info("Intermediate step: Waiting for table [" + tableName + "] to become active before continuing");
GlobalTableOperations.waitForTableActive(primaryClient, tableName);
// Step 2: Convert to MRSC with replica and witness
LOGGER.info("Step 2: Converting to MRSC with replica and witness");
convertToMRSCWithWitness(primaryClient, tableName, replicaRegion, witnessRegion);
// Wait for MRSC conversion to complete using MRSC-specific waiter
LOGGER.info("Waiting for MRSC conversion to complete...");
waitForMRSCReplicasActive(primaryClient, tableName);
LOGGER.info("Intermediate step: Waiting for table [" + tableName + "] to become active before continuing");
GlobalTableOperations.waitForTableActive(primaryClient, tableName);
// Step 3: Verify MRSC configuration
LOGGER.info("Step 3: Verifying MRSC configuration");
describeMRSCTable(primaryClient, tableName);
// Step 4: Test strong consistency with data operations
LOGGER.info("Step 4: Testing strong consistency with data operations");
// Add test item to primary region
putTestItem(primaryClient, tableName, "The Beatles", "Hey Jude", "The Beatles 1967-1970", "1968");
// Immediately read from replica region (no wait needed with MRSC)
LOGGER.info("Reading from replica region immediately (strong consistency):");
GetItemResponse getResponse =
getItemWithConsistentRead(replicaClient, tableName, "The Beatles", "Hey Jude");
if (getResponse.hasItem()) {
LOGGER.info("✓ Strong consistency verified - item immediately available in replica region");
} else {
LOGGER.warning("✗ Item not found in replica region");
}
// Test conditional update from replica region
LOGGER.info("Testing conditional update from replica region:");
performConditionalUpdate(replicaClient, tableName, "The Beatles", "Hey Jude", "5");
LOGGER.info("✓ Conditional update successful - demonstrates strong consistency");
// Step 5: Cleanup
LOGGER.info("Step 5: Cleaning up resources");
cleanupMRSCReplicas(primaryClient, tableName, replicaRegion, witnessRegion);
// Wait for cleanup to complete using basic table waiter
LOGGER.info("Waiting for replica cleanup to complete...");
GlobalTableOperations.waitForTableActive(primaryClient, tableName);
// "Halt" until replica/witness cleanup is complete
DescribeTableResponse cleanupVerification = describeMRSCTable(primaryClient, tableName);
int backoffSeconds = 5; // Start with 5 second intervals
while (cleanupVerification.table().multiRegionConsistency() != null) {
LOGGER.info("Waiting additional time (" + backoffSeconds + " seconds) for MRSC cleanup to complete...");
tempWait(backoffSeconds);
// Exponential backoff with cap
backoffSeconds = Math.min(backoffSeconds * 2, 30);
cleanupVerification = describeMRSCTable(primaryClient, tableName);
}
// Delete the primary table
deleteTable(primaryClient, tableName);
LOGGER.info("=== MRSC Workflow Demonstration Complete ===");
LOGGER.info("");
LOGGER.info("Key benefits of Multi-Region Strong Consistency (MRSC):");
LOGGER.info("- Immediate consistency across all regions (no eventual consistency delays)");
LOGGER.info("- Simplified application logic (no need to handle eventual consistency)");
LOGGER.info("- Support for conditional writes and transactions across regions");
LOGGER.info("- Consistent read operations from any region without waiting");
} catch (DynamoDbException | InterruptedException e) {
LOGGER.severe("MRSC workflow failed: " + e.getMessage());
throw e;
}
}
