Abstract: Embodiments of this specification provide methods for configuring nodes in a distributed database, methods for synchronizing transaction logs in the distributed database, and the nodes in the distributed database. One method for configuring nodes includes: determining a first quantity of first nodes from N nodes in the distributed database, wherein the first nodes comprise a master node configured to synchronize transactions, the first quantity is an integer greater than N/2, and the first nodes determine a first transaction based on a distributed consistency protocol, and determining one or more of remaining nodes other than the first nodes in the N nodes as asynchronous nodes or election nodes, wherein the asynchronous nodes are configured to asynchronously receive the first transaction from the master node, and the election nodes are configured to modify at least the master node.

Abstract: Embodiments of this specification provide a method and an apparatus for synchronously updating metadata in a distributed database. The distributed database includes a plurality of database nodes. A first node stores a first primary replica of a target replicated table, and a plurality of remaining second nodes store first backup replicas of the target replicated table. A full synchronization protocol is used between the first primary replica and the first backup replicas. The method is applied to the first node and includes: receiving an update request related to first metadata of a first data table in the distributed database; and writing update information related to the first metadata into the first primary replica based on the update request, to synchronize the update information to the respective first backup replicas of the plurality of second nodes based on the full synchronization protocol.

Abstract: Disclosed are a method and system for redundancy switch between two controllers for supplementary damping of a governor, relating to the technical field of control methods. The method includes acquiring a participation condition according to an output result, listing the participation condition in a truth value table and supplementing correlation logic; outputting the correlation logic as an image language, and simplifying the image language; and acquiring switch logic by a simplified image language, and transforming the switch logic into a programming language of the controller. A complex control relation can be decomposed in the disclosure, so that the difficulty can be reduced, and a correct and comprehensive control purpose can be achieved. Moreover, the method has universality.

Abstract: Embodiments of this specification provide methods for configuring nodes in a distributed database, methods for synchronizing transaction logs in the distributed database, and the nodes in the distributed database. One method for configuring nodes includes: determining a first quantity of first nodes from N nodes in the distributed database, wherein the first nodes comprise a master node configured to synchronize transactions, the first quantity is an integer greater than N/2, and the first nodes determine a first transaction based on a distributed consistency protocol, and determining one or more of remaining nodes other than the first nodes in the N nodes as asynchronous nodes or election nodes, wherein the asynchronous nodes are configured to asynchronously receive the first transaction from the master node, and the election nodes are configured to modify at least the master node.

Abstract: Embodiments of this specification provide a method and an apparatus for synchronously updating metadata in a distributed database. The distributed database includes a plurality of database nodes. A first node stores a first primary replica of a target replicated table, and a plurality of remaining second nodes store first backup replicas of the target replicated table. A full synchronization protocol is used between the first primary replica and the first backup replicas. The method is applied to the first node and includes: receiving an update request related to first metadata of a first data table in the distributed database; and writing update information related to the first metadata into the first primary replica based on the update request, to synchronize the update information to the respective first backup replicas of the plurality of second nodes based on the full synchronization protocol.