1. A computer-implemented method, comprising: monitoring a plurality of resource usages on a node; granting to a plurality of database processes, by a resource control mechanism of the node, one or more locks, each lock of said one or more locks granting access to one or more specified shared data blocks of a database; determining whether a resource usage in the plurality of resource usages exceeds a resource usage threshold; and when the resource usage in the plurality of resource usages exceeds the resource usage threshold, implementing one or more resource usage reduction policies, by the resource control mechanism, to restrict access to one or more particular shared data blocks of the database by delaying or denying one or more requested locks corresponding to the one or more particular shared data blocks; wherein the method is performed by one or more computing devices.