Database interface to obtain item state on conditional operation failure

Abstract

Systems and methods are provided to implement a database system configured to return the state of a data item upon failure of a condition check on the data item during a conditional write. In embodiments, a write request may specify an indicator to return the item state upon condition failure. The request may specify multiple database operations to execute as a transaction, where failure of a single condition check will cause the entire transaction to fail and an item state causing the failure to be returned. The returned state of the data item may include a selection of the item's attributes specified by the request. Advantageously, these features allow a client to easily obtain the precise cause of a write's failure. Moreover, because the item state is returned only when a conditional write fails and only when requested, the response size of most write requests remains unchanged.