Batch Write Item

dynamodb_batch_write_item

R Documentation

The BatchWriteItem operation puts or deletes multiple items in one or more tables

Description

The batch_write_item operation puts or deletes multiple items in one or more tables. A single call to batch_write_item 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.

batch_write_item cannot update items. If you perform a batch_write_item 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 update_item action.

The individual put_item and delete_item operations specified in batch_write_item are atomic; however batch_write_item 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 batch_write_item in a loop. Each iteration would check for unprocessed items and submit a new batch_write_item 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 batch_write_item 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 batch_write_item 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 batch_write_item, 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, batch_write_item does not behave in the same way as individual put_item and delete_item calls would. For example, you cannot specify conditions on individual put and delete requests, and batch_write_item 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, batch_write_item 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 batch_write_item 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 batch_write_item request. For example, you cannot put and delete the same item in the same batch_write_item 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.

Usage

dynamodb_batch_write_item(RequestItems, ReturnConsumedCapacity,
  ReturnItemCollectionMetrics)

Arguments

RequestItems

[required] A map of one or more table names or table ARNs 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 delete_item 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 put_item 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.

ReturnConsumedCapacity

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.

Value

A list with the following syntax:

list(
  UnprocessedItems = list(
    list(
      list(
        PutRequest = list(
          Item = list(
            list(
              S = "string",
              N = "string",
              B = raw,
              SS = list(
                "string"
              ),
              NS = list(
                "string"
              ),
              BS = list(
                raw
              ),
              M = list(
                list()
              ),
              L = list(
                list()
              ),
              NULL = TRUE|FALSE,
              BOOL = TRUE|FALSE
            )
          )
        ),
        DeleteRequest = list(
          Key = list(
            list(
              S = "string",
              N = "string",
              B = raw,
              SS = list(
                "string"
              ),
              NS = list(
                "string"
              ),
              BS = list(
                raw
              ),
              M = list(
                list()
              ),
              L = list(
                list()
              ),
              NULL = TRUE|FALSE,
              BOOL = TRUE|FALSE
            )
          )
        )
      )
    )
  ),
  ItemCollectionMetrics = list(
    list(
      list(
        ItemCollectionKey = list(
          list(
            S = "string",
            N = "string",
            B = raw,
            SS = list(
              "string"
            ),
            NS = list(
              "string"
            ),
            BS = list(
              raw
            ),
            M = list(
              list()
            ),
            L = list(
              list()
            ),
            NULL = TRUE|FALSE,
            BOOL = TRUE|FALSE
          )
        ),
        SizeEstimateRangeGB = list(
          123.0
        )
      )
    )
  ),
  ConsumedCapacity = list(
    list(
      TableName = "string",
      CapacityUnits = 123.0,
      ReadCapacityUnits = 123.0,
      WriteCapacityUnits = 123.0,
      Table = list(
        ReadCapacityUnits = 123.0,
        WriteCapacityUnits = 123.0,
        CapacityUnits = 123.0
      ),
      LocalSecondaryIndexes = list(
        list(
          ReadCapacityUnits = 123.0,
          WriteCapacityUnits = 123.0,
          CapacityUnits = 123.0
        )
      ),
      GlobalSecondaryIndexes = list(
        list(
          ReadCapacityUnits = 123.0,
          WriteCapacityUnits = 123.0,
          CapacityUnits = 123.0
        )
      )
    )
  )
)

Request syntax

svc$batch_write_item(
  RequestItems = list(
    list(
      list(
        PutRequest = list(
          Item = list(
            list(
              S = "string",
              N = "string",
              B = raw,
              SS = list(
                "string"
              ),
              NS = list(
                "string"
              ),
              BS = list(
                raw
              ),
              M = list(
                list()
              ),
              L = list(
                list()
              ),
              NULL = TRUE|FALSE,
              BOOL = TRUE|FALSE
            )
          )
        ),
        DeleteRequest = list(
          Key = list(
            list(
              S = "string",
              N = "string",
              B = raw,
              SS = list(
                "string"
              ),
              NS = list(
                "string"
              ),
              BS = list(
                raw
              ),
              M = list(
                list()
              ),
              L = list(
                list()
              ),
              NULL = TRUE|FALSE,
              BOOL = TRUE|FALSE
            )
          )
        )
      )
    )
  ),
  ReturnConsumedCapacity = "INDEXES"|"TOTAL"|"NONE",
  ReturnItemCollectionMetrics = "SIZE"|"NONE"
)

Examples

## Not run: 
# This example adds three new items to the Music table using a batch of
# three PutItem requests.
svc$batch_write_item(
  RequestItems = list(
    Music = list(
      list(
        PutRequest = list(
          Item = list(
            AlbumTitle = list(
              S = "Somewhat Famous"
            ),
            Artist = list(
              S = "No One You Know"
            ),
            SongTitle = list(
              S = "Call Me Today"
            )
          )
        )
      ),
      list(
        PutRequest = list(
          Item = list(
            AlbumTitle = list(
              S = "Songs About Life"
            ),
            Artist = list(
              S = "Acme Band"
            ),
            SongTitle = list(
              S = "Happy Day"
            )
          )
        )
      ),
      list(
        PutRequest = list(
          Item = list(
            AlbumTitle = list(
              S = "Blue Sky Blues"
            ),
            Artist = list(
              S = "No One You Know"
            ),
            SongTitle = list(
              S = "Scared of My Shadow"
            )
          )
        )
      )
    )
  )
)

## End(Not run)