Method for maximizing throughput and minimizing transactions response times on the primary system in the presence of a zero data loss standby replica

摘要

A method and system is provided for reducing delay to applications connected to a database server that guarantees no data loss during failure or disaster. After storing a log record persistently in a local primary log, the log writer returns control to the application which continues running concurrently with the database server sending the session's log records to a standby database. A separate back channel is used by the standby to communicate, out-of-band to the primary, the location of the last log record stored persistently to the standby log. An application waiting for a transaction to commit may wait until the transaction's commit record has been persisted. Also described is a technique for reducing application delay when there is contention between nodes of a multi-node cluster for updating the same block. The technique provides for an asynchronous ping protocol that guarantees zero data loss during failure or disaster.