Table of Contents

Class BatchWriteItemRequest

Namespace
Amazon.DynamoDBv2.Model
Assembly
AWSSDK.DynamoDBv2.dll

Container for the parameters to the BatchWriteItem operation. 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.
note

BatchWriteItem
cannot update items. To update items, 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.

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
.

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 same 
    BatchWriteItem
    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. 

public class BatchWriteItemRequest : AmazonDynamoDBRequest
Inheritance
BatchWriteItemRequest

Constructors

BatchWriteItemRequest()

Empty constructor used to set properties independently even when a simple constructor is available

public BatchWriteItemRequest()

BatchWriteItemRequest(Dictionary<string, List<WriteRequest>>)

Instantiates BatchWriteItemRequest with the parameterized properties

public BatchWriteItemRequest(Dictionary<string, List<WriteRequest>> requestItems)

Parameters

requestItems Dictionary<string, List<WriteRequest>>

A map of one or more table names and, for each table, a list of operations to be performed (

DeleteRequest
or 
PutRequest
). Each element in the map consists of the following: 
  • DeleteRequest
    - Perform a 
    DeleteItem
    operation on the specified item. The item to be deleted is identified by a 
    Key
    subelement: 
    • Key
      - A map of primary key attribute values that uniquely identify the item. Each entry in this map consists of an attribute name and an attribute value. For each primary key, you must provide all of the key attributes. For example, with a simple primary key, you only need to provide a value for the partition key. For a composite primary key, you must provide values for both the partition key and the sort key. 
  • PutRequest
    - Perform a 
    PutItem
    operation on the specified item. The item to be put is identified by an 
    Item
    subelement: 
    • Item
      - A map of attributes and their values. Each entry in this map consists of an attribute name and an attribute value. Attribute values must not be null; string and binary type attributes must have lengths greater than zero; and set type attributes must not be empty. Requests that contain empty values are rejected with a 
      ValidationException
      exception. If you specify any attributes that are part of an index key, then the data types for those attributes must match those of the schema in the table's attribute definition.

Properties

RequestItems

Gets and sets the property RequestItems.

A map of one or more table names and, for each table, a list of operations to be performed (

DeleteRequest
or 
PutRequest
). Each element in the map consists of the following: 

  • DeleteRequest
    - Perform a 
    DeleteItem
    operation on the specified item. The item to be deleted is identified by a 
    Key
    subelement: 

    • Key
      - A map of primary key attribute values that uniquely identify the item. Each entry in this map consists of an attribute name and an attribute value. For each primary key, you must provide all of the key attributes. For example, with a simple primary key, you only need to provide a value for the partition key. For a composite primary key, you must provide values for both the partition key and the sort key. 

  • PutRequest
    - Perform a 
    PutItem
    operation on the specified item. The item to be put is identified by an 
    Item
    subelement: 

    • Item
      - A map of attributes and their values. Each entry in this map consists of an attribute name and an attribute value. Attribute values must not be null; string and binary type attributes must have lengths greater than zero; and set type attributes must not be empty. Requests that contain empty values are rejected with a 
      ValidationException
      exception.

      If you specify any attributes that are part of an index key, then the data types for those attributes must match those of the schema in the table's attribute definition. 

public Dictionary<string, List<WriteRequest>> RequestItems { get; set; }

Property Value

Dictionary<string, List<WriteRequest>>

ReturnConsumedCapacity

Gets and sets the property ReturnConsumedCapacity.

public ReturnConsumedCapacity ReturnConsumedCapacity { get; set; }

Property Value

ReturnConsumedCapacity

ReturnItemCollectionMetrics

Gets and sets the property ReturnItemCollectionMetrics.

Determines whether item collection metrics are returned. If set to 

SIZE
, the response includes statistics about item collections, if any, that were modified during the operation are returned in the response. If set to 
NONE
(the default), no statistics are returned. 
public ReturnItemCollectionMetrics ReturnItemCollectionMetrics { get; set; }

Property Value

ReturnItemCollectionMetrics