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Amazon.DynamoDBv2.Model.BatchWriteItemRequest Class Reference

Container for the parameters to the BatchWriteItem operation. More...

Inheritance diagram for Amazon.DynamoDBv2.Model.BatchWriteItemRequest:
Amazon.DynamoDBv2.AmazonDynamoDBv2Request

Properties

Dictionary< string, List
< WriteRequest > > 
RequestItems [get, set]
 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: More...
 
ReturnConsumedCapacity ReturnConsumedCapacity [get, set]
 If set to TOTAL, ConsumedCapacity is included in the response; if set to NONE (the default), ConsumedCapacity is not included. More...
 
ReturnItemCollectionMetrics ReturnItemCollectionMetrics [get, set]
 If set to SIZE, 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.. More...
 

Detailed Description

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 write up to 1 MB of data, which can comprise as many as 25 put or delete requests. Individual items to be written can be as large as 64 KB.

NOTE: BatchWriteItem cannot update items. To update items, use the UpdateItem API.

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.

To write one item, you can use the PutItem operation; to delete one item, you can use the DeleteItem operation.

With BatchWriteItem , you can efficiently write or delete large amounts of data, such as from Amazon Elastic MapReduce (EMR), or copy data from another database into Amazon 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, such as Java, 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, such as PHP, BatchWriteItem will write or delete the specified items one at a time. In both situations, BatchWriteItem provides an alternative where the API 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, Amazon 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.

The total request size exceeds 1 MB.

Any individual item in a batch exceeds 64 KB.

Property Documentation

Dictionary<string,List<WriteRequest> > Amazon.DynamoDBv2.Model.BatchWriteItemRequest.RequestItems
getset

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.
  • 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 will be rejected with a ValidationException. 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.

Constraints:

  • Length 1 - 25
ReturnConsumedCapacity Amazon.DynamoDBv2.Model.BatchWriteItemRequest.ReturnConsumedCapacity
getset

If set to TOTAL, ConsumedCapacity is included in the response; if set to NONE (the default), ConsumedCapacity is not included.

Constraints:

  • Allowed Values INDEXES, TOTAL, NONE
ReturnItemCollectionMetrics Amazon.DynamoDBv2.Model.BatchWriteItemRequest.ReturnItemCollectionMetrics
getset

If set to SIZE, 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..

Constraints:

  • Allowed Values SIZE, NONE

The documentation for this class was generated from the following file: