A generalized architecture for a highly available transaction processing system that combines commercially available components and software components specifically developed to implement the architecture into an integrated, highly available transaction processing system that minimizes planned and unplanned downtime, minimizes data loss in the event of failures, provides proactive monitoring of both hardware and software components of the highly available transaction processing system, provides automated recovery actions that involve fast failover, either locally to an Inactive Node, or remotely to a Standby Site, and provides an easy-to-use graphical-user-interface-based management interface that provides service-oriented views of the state of the system, with context-directed commands and meta-commands to guide managers in execution of their tasks.
Techniques for reducing commit latency in a database system having a primary database system and a standby database system that is receiving a stream of redo data items from the primary. The standby sends an acknowledgment for a received item of redo data before the standby writes the redo data item to a redo log for the stream. When a no more redo event occurs in the standby, the standby sets a "no data lost flag" in the redo log if the stream of redo data items has no gaps and all of the redo data items received in the standby have been written to the redo log. The database system may operate in a first mode in which an acknowledgment is sent as just described and a second mode in which an acknowledgment is sent after the redo data item has been written to the redo log.
The present invention provides a novel system and method for failover. In an embodiment, a primary server and a backup server are available to a plurality of clients. Messages containing requests are processed by the primary server, while a mirror image of transaction records generated by the processing of those requests is maintained in volatile memory of both the primary server and the backup server. In this mode of operation, the volatile memory is periodically flushed to non-volatile memory.
A graphical user interface based method of configuring automatic failover from a primary database system to a standby database system that is coupled to the primary database system by a network. Also coupled to the network is an observer process that is independent of the database systems and that initiates the failover process. The observer periodically pings the database systems to determine whether a failover is necessary. The graphical user interface permits a user to specify the primary and secondary database systems, configure the observer, and specify conditions under which a failover may occur and to enable automatic failover. A failover context is created from the inputs to the GUI and stored in persistent storage belonging to the database systems. If the Observer's context is stale, the Observer fetches the database system's context.
A method and system of copying memory from a source processor to a target processor by duplicating memory writes. At least some of the exemplary embodiments may be a method comprising stopping execution of a user program on a target processor (the target processor coupled to a first memory), continuing to execute a duplicate copy of the user program on a source processor (the source processor coupled to a second memory and generating writes to the second memory), duplicating memory writes of the source processor and duplicating writes by input/output adapters to create a stream of duplicate memory writes, and applying the duplicated memory writes to the first memory.
