Abstract: Technologies are described providing adaptive query routing in a replicated database environment. The technologies can be used with a variety of replication protocols. Prepared statements, such as for queries, from a database client can be routed to a source node, or a source node and available replica nodes, when a replica node becomes unavailable. When a replica node becomes available again, a prepared statement can be updated to indicate that the updated prepared statement can be executed at nodes including the replica node that is available again. Prepared statement routing can also be used when a portion of replicated data becomes unavailable at a replica node, but a portion of replicated data remains available.

Abstract: The present invention relates to a linear motion engine, wherein four cylinders are arranged in two laterally opposing rows with each of their respective piston rods sharing common linkage to a slider located in midway between the two-cylinder rows and connected to the eccentric crank shafts of a flywheel; and whereby each cylinder piston goes through an alternate linear motion comprising four steps of strokes of intake, compression, combustion and exhaust, constituting an engine unit capable of delivering power output through linear motion of the slider itself, subsequently contributing to an elimination of power loss from circular motion changeover and enabling to produce a compact engine suitable for work machines operated by linear motion.