Abstract: A method for allocating memory in a computing device having a non-volatile main memory is described. The method comprises receiving, by a memory allocator, a request for non-volatile memory allocation of an object from a program executing on the computing device, the request comprising a requested memory size and registration data from the program. The method comprises finding an available address of one of a plurality of portions of a page of the non-volatile memory and searching an active page table in the non-volatile main memory to find the page and if the page is not found in the active page table: inserting the page into the active page table; and waiting for a memory write for inserting the page into the active page table to complete.

Abstract: A method for allocating memory in a computing device having a non-volatile main memory is described. The method comprises receiving, by a memory allocator, a request for non-volatile memory allocation of an object from a program executing on the computing device, the request comprising a requested memory size and registration data from the program. The method comprises finding an available address of one of a plurality of portions of a page of the non-volatile memory and searching an active page table in the non-volatile main memory to find the page and if the page is not found in the active page table: inserting the page into the active page table; and waiting for a memory write for inserting the page into the active page table to complete.

Abstract: A method for allocating memory in a computing device having a non-volatile main memory is described. The method comprises receiving, by a memory allocator, a request for non-volatile memory allocation of an object from a program executing on the computing device, the request comprising a requested memory size and registration data from the program. The method comprises finding an available address of one of a plurality of portions of a page of the non-volatile memory and searching an active page table in the non-volatile main memory to find the page and if the page is not found in the active page table: inserting the page into the active page table; and waiting for a memory write for inserting the page into the active page table to complete.

Abstract: In various examples, there is provided methods performed by nodes in a cluster of nodes to establish a master clock at a new master node following a reconfiguration of the nodes included in the cluster, whereby the master clock is provided by an old master node prior to the reconfiguration, and synchronize a local clock of slave nodes to clock of the new master node. The new master node sends a message to the slave nodes instructing them to disable their respective local clocks, receives acknowledgements that the local clocks have been disabled, waits until a time at which all leases have expired for any nodes removed from the cluster, sets the value of its clock to be greater than a maximum value that could have been provided by the old master node at the time the leases expired and indicates to the other nodes to re-enable their local clocks.

Abstract: A method for allocating memory in a computing device having a non-volatile main memory is described. The method comprises receiving, by a memory allocator, a request for non-volatile memory allocation of an object from a program executing on the computing device, the request comprising a requested memory size and registration data from the program. The method comprises finding an available address of one of a plurality of portions of a page of the non-volatile memory and searching an active page table in the non-volatile main memory to find the page and if the page is not found in the active page table: inserting the page into the active page table; and waiting for a memory write for inserting the page into the active page table to complete.

Abstract: In various examples, there is provided methods performed by nodes in a cluster of nodes for performing transactions comprising one or more read operations and/or one or more write operations. The node comprises a local clock which is synchronized with a master clock and maintains a measure of uncertainty indicating current minimum and maximum values of the master clock. The method to perform transactions involving read operations generates a read timestamp representing a point in time which is earlier than a current minimum value of the master clock. The method then reads the objects and determines, for each of them, whether a timestamp associated with that object is later than the read timestamp. If so, an error handling procedure is performed for that object.

Abstract: A method for allocating memory in a computing device having a non-volatile main memory is described. The method comprises receiving, by a memory allocator, a request for non-volatile memory allocation of an object from a program executing on the computing device, the request comprising a requested memory size and registration data from the program. The method comprises finding an available address of one of a plurality of portions of a page of the non-volatile memory and searching an active page table in the non-volatile main memory to find the page and if the page is not found in the active page table: inserting the page into the active page table; and waiting for a memory write for inserting the page into the active page table to complete.

Abstract: A distributed graph database that enables scaling and efficient processing is described. The distributed graph database can, for example, scale up to petabytes of data to enable transactional processing of graph data with low latency and low processing overhead. The distributed graph database can include a cluster of devices and a remote direct memory access (RDMA)-based communication layer to perform low latency messaging between devices of the cluster of devices. Additionally, the distributed graph database can include a shared memory layer that provides one or more data structures, a transaction layer to facilitate query processing, and a graph database layer stored in computer-readable media and executed on a processor to implement a graph data model. In at least one example, the graph data model can be mapped to the one or more data structures.

Abstract: In various examples, there is provided methods performed by nodes in a cluster of nodes to establish a master clock at a new master node following a reconfiguration of the nodes included in the cluster, whereby the master clock is provided by an old master node prior to the reconfiguration, and synchronize a local clock of slave nodes to clock of the new master node. The new master node sends a message to the slave nodes instructing them to disable their respective local clocks, receives acknowledgements that the local clocks have been disabled, waits until a time at which all leases have expired for any nodes removed from the cluster, sets the value of its clock to be greater than a maximum value that could have been provided by the old master node at the time the leases expired and indicates to the other nodes to re-enable their local clocks.

Abstract: A server at a cluster of servers in a data center is described. The server comprises a memory which is part of a distributed memory of the cluster. The server has at least one processor executing transactions and lock-free reads on software objects stored in regions of the distributed memory, the software objects and details of the transactions being replicated in the distributed memory. The server has a network interface card arranged to receive a message indicating a new configuration of the cluster comprising addition, removal or potential failure of at least one of the other servers. The processor is configured to use a recovery process which enables the lock-free reads and committed ones of the transactions to retain the properties of atomicity, consistency, isolation and durability across configuration changes.

Abstract: In various examples, there is provided methods performed by nodes in a cluster of nodes to establish a master clock at a new master node following a reconfiguration of the nodes included in the cluster, whereby the master clock is provided by an old master node prior to the reconfiguration, and synchronize a local clock of slave nodes to clock of the new master node. The new master node sends a message to the slave nodes instructing them to disable their respective local clocks, receives acknowledgements that the local clocks have been disabled, waits until a time at which all leases have expired for any nodes removed from the cluster, sets the value of its clock to be greater than a maximum value that could have been provided by the old master node at the time the leases expired and indicates to the other nodes to re-enable their local clocks.

Abstract: In various examples, there is provided methods performed by nodes in a cluster of nodes for performing transactions comprising one or more read operations and/or one or more write operations. The node comprises a local clock which is synchronized with a master clock and maintains a measure of uncertainty indicating current minimum and maximum values of the master clock. The method to perform transactions involving read operations generates a read timestamp representing a point in time which is earlier than a current minimum value of the master clock. The method then reads the objects and determines, for each of them, whether a timestamp associated with that object is later than the read timestamp. If so, an error handling procedure is performed for that object.

Abstract: In various examples, there is provided methods performed by nodes in a cluster of nodes to establish a master clock at a new master node following a reconfiguration of the nodes included in the cluster, whereby the master clock is provided by an old master node prior to the reconfiguration, and synchronize a local clock of slave nodes to clock of the new master node. The new master node sends a message to the slave nodes instructing them to disable their respective local clocks, receives acknowledgements that the local clocks have been disabled, waits until a time at which all leases have expired for any nodes removed from the cluster, sets the value of its clock to be greater than a maximum value that could have been provided by the old master node at the time the leases expired and indicates to the other nodes to re-enable their local clocks.

Abstract: A method for allocating memory in a computing device having a non-volatile main memory is described. The method comprises receiving, by a memory allocator, a request for non-volatile memory allocation of an object from a program executing on the computing device, the request comprising a requested memory size and registration data from the program. The method comprises finding an available address of one of a plurality of portions of a page of the non-volatile memory and searching an active page table in the non-volatile main memory to find the page and if the page is not found in the active page table: inserting the page into the active page table; and waiting for a memory write for inserting the page into the active page table to complete.

Abstract: A distributed graph database that enables scaling and efficient processing is described. The distributed graph database can, for example, scale up to petabytes of data to enable transactional processing of graph data with low latency and low processing overhead. The distributed graph database can include a cluster of devices and a remote direct memory access (RDMA)-based communication layer to perform low latency messaging between devices of the cluster of devices. Additionally, the distributed graph database can include a shared memory layer that provides one or more data structures, a transaction layer to facilitate query processing, and a graph database layer stored in computer-readable media and executed on a processor to implement a graph data model. In at least one example, the graph data model can be mapped to the one or more data structures.

Abstract: A server at a cluster of servers in a data center is described. The server comprises a memory which is part of a distributed memory of the cluster. The server has at least one processor executing transactions and lock-free reads on software objects stored in regions of the distributed memory, the software objects and details of the transactions being replicated in the distributed memory. The server has a network interface card arranged to receive a message indicating a new configuration of the cluster comprising addition, removal or potential failure of at least one of the other servers. The processor is configured to use a recovery process which enables the lock-free reads and committed ones of the transactions to retain the properties of atomicity, consistency, isolation and durability across configuration changes.

Abstract: The systems and methods described herein may be used to implement a shared dynamic-sized data structure using hardware transactional memory to simplify and/or improve memory management of the data structure. An application (or thread thereof) may indicate (or register) the intended use of an element of the data structure and may initialize the value of the data structure element. Thereafter, another thread or application may use hardware transactions to access the data structure element while confirming that the data structure element is still part of the dynamic data structure and/or that memory allocated to the data structure element has not been freed. Various indicators may be used determine whether memory allocated to the element can be freed.

Abstract: The systems and methods described herein may be used to implement a shared dynamic-sized data structure using hardware transactional memory to simplify and/or improve memory management of the data structure. An application (or thread thereof) may indicate (or register) the intended use of an element of the data structure and may initialize the value of the data structure element. Thereafter, another thread or application may use hardware transactions to access the data structure element while confirming that the data structure element is still part of the dynamic data structure and/or that memory allocated to the data structure element has not been freed. Various indicators may be used determine whether memory allocated to the element element can be freed.

Abstract: Systems and methods for optimizing transactional memory operations may employ static analysis of source code and static caching of memory objects to elide redundant transactional accesses. For example, a compiler (or an optimizer thereof) may be configured to analyze code that includes an atomic transaction to determine if any read accesses to shared memory locations are dominated by a previous read or write access to the same locations and/or any write accesses to shared memory locations are post-dominated by a subsequent write access to the same locations. Any access within a transaction that is determined to be redundant (e.g., any access other than the first read of a given shared memory location from within the transaction or the last write to a given shared memory location from within the transaction) may be replaced (by the compiler/optimizer) with a non-transactional access to a cached shadow copy of the shared memory location.