processing is provided for operating an in - memory database , wherein transaction data is stored by a persistence buffer in an fifo queue , and update processor subsequently : waits for a trigger ; extracts the last transactional data associated with a single transaction of the in - memory database from the fifo memory queue ; determines if the transaction data includes updates to data fields in the in - memory database which were already processed ; and if not , then stores the extracted transaction data to a store queue , remembering the fields updated in the in - memory database , or otherwise updates the store queue with the extracted transaction data . the process continues until the extracting is complete , and the content of the store queue is periodically written into a persistent storage device .