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BatchWriteItemCommand
The BatchWriteItem
operation puts or deletes multiple items in one or more tables. A single call to BatchWriteItem
can transmit up to 16MB of data over the network, consisting of up to 25 item put or delete operations. While individual items can be up to 400 KB once stored, it's important to note that an item's representation might be greater than 400KB while being sent in DynamoDB's JSON format for the API call. For more details on this distinction, see Naming Rules and Data Types .
BatchWriteItem
cannot update items. If you perform a BatchWriteItem
operation on an existing item, that item's values will be overwritten by the operation and it will appear like it was updated. To update items, we recommend you use the UpdateItem
action.
The individual PutItem
and DeleteItem
operations specified in BatchWriteItem
are atomic; however BatchWriteItem
as a whole is not. If any requested operations fail because the table's provisioned throughput is exceeded or an internal processing failure occurs, the failed operations are returned in the UnprocessedItems
response parameter. You can investigate and optionally resend the requests. Typically, you would call BatchWriteItem
in a loop. Each iteration would check for unprocessed items and submit a new BatchWriteItem
request with those unprocessed items until all items have been processed.
For tables and indexes with provisioned capacity, if none of the items can be processed due to insufficient provisioned throughput on all of the tables in the request, then BatchWriteItem
returns a ProvisionedThroughputExceededException
. For all tables and indexes, if none of the items can be processed due to other throttling scenarios (such as exceeding partition level limits), then BatchWriteItem
returns a ThrottlingException
.
If DynamoDB returns any unprocessed items, you should retry the batch operation on those items. However, we strongly recommend that you use an exponential backoff algorithm. If you retry the batch operation immediately, the underlying read or write requests can still fail due to throttling on the individual tables. If you delay the batch operation using exponential backoff, the individual requests in the batch are much more likely to succeed.
For more information, see Batch Operations and Error Handling in the Amazon DynamoDB Developer Guide.
With BatchWriteItem
, you can efficiently write or delete large amounts of data, such as from Amazon EMR, or copy data from another database into DynamoDB. In order to improve performance with these large-scale operations, BatchWriteItem
does not behave in the same way as individual PutItem
and DeleteItem
calls would. For example, you cannot specify conditions on individual put and delete requests, and BatchWriteItem
does not return deleted items in the response.
If you use a programming language that supports concurrency, you can use threads to write items in parallel. Your application must include the necessary logic to manage the threads. With languages that don't support threading, you must update or delete the specified items one at a time. In both situations, BatchWriteItem
performs the specified put and delete operations in parallel, giving you the power of the thread pool approach without having to introduce complexity into your application.
Parallel processing reduces latency, but each specified put and delete request consumes the same number of write capacity units whether it is processed in parallel or not. Delete operations on nonexistent items consume one write capacity unit.
If one or more of the following is true, DynamoDB rejects the entire batch write operation:
-
One or more tables specified in the
BatchWriteItem
request does not exist. -
Primary key attributes specified on an item in the request do not match those in the corresponding table's primary key schema.
-
You try to perform multiple operations on the same item in the same
BatchWriteItem
request. For example, you cannot put and delete the same item in the sameBatchWriteItem
request. -
Your request contains at least two items with identical hash and range keys (which essentially is two put operations).
-
There are more than 25 requests in the batch.
-
Any individual item in a batch exceeds 400 KB.
-
The total request size exceeds 16 MB.
-
Any individual items with keys exceeding the key length limits. For a partition key, the limit is 2048 bytes and for a sort key, the limit is 1024 bytes.
Example Syntax
Use a bare-bones client and the command you need to make an API call.
import { DynamoDBClient, BatchWriteItemCommand } from "@aws-sdk/client-dynamodb"; // ES Modules import
// const { DynamoDBClient, BatchWriteItemCommand } = require("@aws-sdk/client-dynamodb"); // CommonJS import
const client = new DynamoDBClient(config);
const input = { // BatchWriteItemInput
RequestItems: { // BatchWriteItemRequestMap // required
"<keys>": [ // WriteRequests
{ // WriteRequest
PutRequest: { // PutRequest
Item: { // PutItemInputAttributeMap // required
"<keys>": { // AttributeValue Union: only one key present
S: "STRING_VALUE",
N: "STRING_VALUE",
B: new Uint8Array(), // e.g. Buffer.from("") or new TextEncoder().encode("")
SS: [ // StringSetAttributeValue
"STRING_VALUE",
],
NS: [ // NumberSetAttributeValue
"STRING_VALUE",
],
BS: [ // BinarySetAttributeValue
new Uint8Array(), // e.g. Buffer.from("") or new TextEncoder().encode("")
],
M: { // MapAttributeValue
"<keys>": {// Union: only one key present
S: "STRING_VALUE",
N: "STRING_VALUE",
B: new Uint8Array(), // e.g. Buffer.from("") or new TextEncoder().encode("")
SS: [
"STRING_VALUE",
],
NS: [
"STRING_VALUE",
],
BS: [
new Uint8Array(), // e.g. Buffer.from("") or new TextEncoder().encode("")
],
M: {
"<keys>": "<AttributeValue>",
},
L: [ // ListAttributeValue
"<AttributeValue>",
],
NULL: true || false,
BOOL: true || false,
},
},
L: [
"<AttributeValue>",
],
NULL: true || false,
BOOL: true || false,
},
},
},
DeleteRequest: { // DeleteRequest
Key: { // Key // required
"<keys>": "<AttributeValue>",
},
},
},
],
},
ReturnConsumedCapacity: "INDEXES" || "TOTAL" || "NONE",
ReturnItemCollectionMetrics: "SIZE" || "NONE",
};
const command = new BatchWriteItemCommand(input);
const response = await client.send(command);
// { // BatchWriteItemOutput
// UnprocessedItems: { // BatchWriteItemRequestMap
// "<keys>": [ // WriteRequests
// { // WriteRequest
// PutRequest: { // PutRequest
// Item: { // PutItemInputAttributeMap // required
// "<keys>": { // AttributeValue Union: only one key present
// S: "STRING_VALUE",
// N: "STRING_VALUE",
// B: new Uint8Array(),
// SS: [ // StringSetAttributeValue
// "STRING_VALUE",
// ],
// NS: [ // NumberSetAttributeValue
// "STRING_VALUE",
// ],
// BS: [ // BinarySetAttributeValue
// new Uint8Array(),
// ],
// M: { // MapAttributeValue
// "<keys>": {// Union: only one key present
// S: "STRING_VALUE",
// N: "STRING_VALUE",
// B: new Uint8Array(),
// SS: [
// "STRING_VALUE",
// ],
// NS: [
// "STRING_VALUE",
// ],
// BS: [
// new Uint8Array(),
// ],
// M: {
// "<keys>": "<AttributeValue>",
// },
// L: [ // ListAttributeValue
// "<AttributeValue>",
// ],
// NULL: true || false,
// BOOL: true || false,
// },
// },
// L: [
// "<AttributeValue>",
// ],
// NULL: true || false,
// BOOL: true || false,
// },
// },
// },
// DeleteRequest: { // DeleteRequest
// Key: { // Key // required
// "<keys>": "<AttributeValue>",
// },
// },
// },
// ],
// },
// ItemCollectionMetrics: { // ItemCollectionMetricsPerTable
// "<keys>": [ // ItemCollectionMetricsMultiple
// { // ItemCollectionMetrics
// ItemCollectionKey: { // ItemCollectionKeyAttributeMap
// "<keys>": "<AttributeValue>",
// },
// SizeEstimateRangeGB: [ // ItemCollectionSizeEstimateRange
// Number("double"),
// ],
// },
// ],
// },
// ConsumedCapacity: [ // ConsumedCapacityMultiple
// { // ConsumedCapacity
// TableName: "STRING_VALUE",
// CapacityUnits: Number("double"),
// ReadCapacityUnits: Number("double"),
// WriteCapacityUnits: Number("double"),
// Table: { // Capacity
// ReadCapacityUnits: Number("double"),
// WriteCapacityUnits: Number("double"),
// CapacityUnits: Number("double"),
// },
// LocalSecondaryIndexes: { // SecondaryIndexesCapacityMap
// "<keys>": {
// ReadCapacityUnits: Number("double"),
// WriteCapacityUnits: Number("double"),
// CapacityUnits: Number("double"),
// },
// },
// GlobalSecondaryIndexes: {
// "<keys>": {
// ReadCapacityUnits: Number("double"),
// WriteCapacityUnits: Number("double"),
// CapacityUnits: Number("double"),
// },
// },
// },
// ],
// };
Example Usage
BatchWriteItemCommand Input
Parameter | Type | Description |
---|
Parameter | Type | Description |
---|---|---|
RequestItems Required | Record<string, WriteRequest[]> | undefined | A map of one or more table names or table ARNs and, for each table, a list of operations to be performed (
|
ReturnConsumedCapacity | ReturnConsumedCapacity | undefined | Determines the level of detail about either provisioned or on-demand throughput consumption that is returned in the response:
|
ReturnItemCollectionMetrics | ReturnItemCollectionMetrics | undefined | Determines whether item collection metrics are returned. If set to |
BatchWriteItemCommand Output
Parameter | Type | Description |
---|
Parameter | Type | Description |
---|---|---|
$metadata Required | ResponseMetadata | Metadata pertaining to this request. |
ConsumedCapacity | ConsumedCapacity[] | undefined | The capacity units consumed by the entire Each element consists of:
|
ItemCollectionMetrics | Record<string, ItemCollectionMetrics[]> | undefined | A list of tables that were processed by Each entry consists of the following subelements:
|
UnprocessedItems | Record<string, WriteRequest[]> | undefined | A map of tables and requests against those tables that were not processed. The Each
If there are no unprocessed items remaining, the response contains an empty |
Throws
Name | Fault | Details |
---|
Name | Fault | Details |
---|---|---|
InternalServerError | server | An error occurred on the server side. |
InvalidEndpointException | client | |
ItemCollectionSizeLimitExceededException | client | An item collection is too large. This exception is only returned for tables that have one or more local secondary indexes. |
ProvisionedThroughputExceededException | client | Your request rate is too high. The Amazon Web Services SDKs for DynamoDB automatically retry requests that receive this exception. Your request is eventually successful, unless your retry queue is too large to finish. Reduce the frequency of requests and use exponential backoff. For more information, go to Error Retries and Exponential Backoff in the Amazon DynamoDB Developer Guide. |
RequestLimitExceeded | client | Throughput exceeds the current throughput quota for your account. Please contact Amazon Web Services Support to request a quota increase. |
ResourceNotFoundException | client | The operation tried to access a nonexistent table or index. The resource might not be specified correctly, or its status might not be |
DynamoDBServiceException | Base exception class for all service exceptions from DynamoDB service. |