Abstract: A system includes processing nodes and shared memory. Each processing node includes a processor and local memory. The local memory of each processing node stores at least a partial copy of the immutable data stage of a dataset. The shared memory is accessible by each processing node and stores a sole copy of the mutable data stage of the dataset and a master copy of the immutable data stage of a dataset.

Abstract: A system includes processing nodes and shared memory. Each processing node includes a processor and local memory. The local memory of each processing node stores at least a partial copy of the immutable data stage of a dataset. The shared memory is accessible by each processing node and stores a sole copy of the mutable data stage of the dataset and a master copy of the immutable data stage of a dataset.

Abstract: Example implementations relate to changing concurrency control modes. An example implementation includes controlling a concurrency control mode of a data slot that stores a data value. A concurrency control mode of a data slot may be changed from an optimistic concurrency control mode to a multi-version concurrency control mode responsive to detecting a read-write conflict for the data slot. A concurrency control mode of a data slot may be changed from a multi-version concurrency control mode to an optimistic concurrency control mode responsive to detecting that the data slot satisfies a low contention criterion.