The BatchPutAttributes operation creates or replaces attributes within one or more items. By using this operation, the client can perform multiple PutAttribute operation with a single call. This helps yield savings in round trips and latencies, enabling Amazon SimpleDB to optimize requests and generally produce better throughput.

The client may specify the item name with the Item.X.ItemName parameter. The client may specify new attributes using a combination of the Item.X.Attribute.Y.Name and Item.X.Attribute.Y.Value parameters. The client may specify the first attribute for the first item using the parameters Item.0.Attribute.0.Name and Item.0.Attribute.0.Value, and for the second attribute for the first item by the parameters Item.0.Attribute.1.Name and Item.0.Attribute.1.Value, and so on.

Attributes are uniquely identified within an item by their name/value combination. For example, a single item can have the attributes { "first_name", "first_value" } and { "first_name", "second_value" }. However, it cannot have two attribute instances where both the Item.X.Attribute.Y.Name and Item.X.Attribute.Y.Value are the same.

Optionally, the requester can supply the Replace parameter for each individual value. Setting this value to true will cause the new attribute values to replace the existing attribute values. For example, if an item I has the attributes { 'a', '1' }, { 'b', '2'} and { 'b', '3' } and the requester does a BatchPutAttributes of {'I', 'b', '4' } with the Replace parameter set to true, the final attributes of the item will be { 'a', '1' } and { 'b', '4' }, replacing the previous values of the 'b' attribute with the new value.

This operation is vulnerable to exceeding the maximum URL size when making a REST request using the HTTP GET method. This operation does not support conditions using Expected.X.Name, Expected.X.Value, or Expected.X.Exists.

You can execute multiple BatchPutAttributes operations and other operations in parallel. However, large numbers of concurrent BatchPutAttributes calls can result in Service Unavailable (503) responses.

The following limitations are enforced for this operation:

• 256 attribute name-value pairs per item
• 1 MB request size
• 1 billion attributes per domain
• 10 GB of total user data storage per domain
• 25 item limit per BatchPutAttributes operation