TransactGetItems is a synchronous operation that atomically retrieves multiple items from one or more tables (but not from indexes) in a single account and Region. A TransactGetItems call can contain up to 100 TransactGetItem objects, each of which contains a Get structure that specifies an item to retrieve from a table in the account and Region. A call to TransactGetItems cannot retrieve items from tables in more than one Amazon Web Services account or Region. The aggregate size of the items in the transaction cannot exceed 4 MB.

DynamoDB rejects the entire TransactGetItems request if any of the following is true:

• A conflicting operation is in the process of updating an item to be read.

• There is insufficient provisioned capacity for the transaction to be completed.

• There is a user error, such as an invalid data format.

• The aggregate size of the items in the transaction exceeded 4 MB.