A request is received, from a mutator thread, to load a first reference to a first object from a heap memory onto a call stack of the application thread. Responsive to receiving the request, a system retrieves the first reference from the heap memory. The system executes a bitwise shift operation that (a) removes one or more bits representing the first garbage collection state and (b) generates a second reference from the first reference. Based on a particular bit, of the one or more bits removed from the first reference by the shift operation, the system determines whether to perform a set of garbage collection operations on the first reference to bring the first reference to a good state. The second reference, without any indication of any of the plurality of garbage collection states, is stored to the call stack.

During execution of garbage collection marking, an application thread receives a first request to overwrite a reference field of an object, the object comprising at least a first reference and the first request comprising a second reference to be written to the reference field. Responsive to receiving the first request, the application thread determines a marking parity for objects being traversed by the garbage collection marking process and loads the first reference from the heap. The application thread determines that marking metadata of the first reference does not match the marking parity. Responsive to that determination, the application thread adds the first reference to a marking list, modifies the second reference to include the current marking parity as the marking metadata, and stores the modified second reference to the first reference field. In subsequent writes to the reference field, the application thread refrains from adding to the marking list.

During execution of garbage collection, an application receives a first request to overwrite a reference field of an object, the object comprising a first reference and the first request comprising a memory address at which the reference field is stored, and a second reference to be written to the reference field. Responsive to receiving the first request, the system determines a current remembered set phase, and loads the first reference. The application determines that remembered set metadata of the first reference does not match the current remembered set phase. Responsive to that determination, the application adds an entry to a remembered set data structure, modifies the second reference to include the current remembered set phase as the remembered set metadata, and stores the modified second reference to the reference field. In subsequent writes to the reference field, the application refrains from adding to the remembered set data structure.

An apparatus is disclosed. The apparatus may be implemented in a database node or a storage node and includes one or more processors and memory storing instructions for causing the processor to perform a number of operations. Responsive to a page write request, the apparatus determines an identifier corresponding to the requested page, sends component blocks corresponding to the page to a storage node for appending to an append-only storage log of the storage node, receives the physical location of the stored component blocks, and associates the physical storage location of the stored component blocks with the logical identifier corresponding to the page.

An arena-based memory management system is disclosed. In response to a call to reclaim memory storing a group of objects allocated in an arena, an object not in use of the group of objects allocated in the arena is collected. A live object of the plurality of objects is copied from the arena to a heap.

Prioritizing garbage collection based on the extent to which data is deduplicated, including: determining, for one or more data elements, a number of deduplicated references to each data element; storing, for each of the data elements, the data element in an area of the storage device that contains other data elements with a similar number of deduplicated references; and adjusting a garbage collection schedule for the storage device, wherein garbage collection operations are performed more frequently on areas of the storage device that contain data elements with a relatively low number of deduplicated references.

The disclosed embodiments provide a method, apparatus, and system for selecting, based on feedback from previous garbage collections, a portion of a referenced memory area for garbage collection within a time window. During the execution of a software program, the system selects a given portion of a referenced memory area on which garbage collection can be completed within the given time window and attempts to complete garbage collection on at least the given portion of the referenced memory area before the end of the given time window. Next, the system selects, based on the results of the garbage collection performed during the given time window, a subsequent portion of the referenced memory area on which garbage collection can be completed within the subsequent time window and attempts to complete garbage collection on at least the subsequent portion of the referenced memory area before the end of the subsequent time window.

A method of testing production server applications. The method comprises monitoring a production server that is executing a first version of a production application by an agent application executing on the production server, recording changes made on the production server by the agent application in a reporting file on the production server, launching a test application on a test server, wherein the test application is associated with a second version of the production application, in response to launching the test application, reading the reporting file by a script executing on the test server, determining by the script that changes were made on the production server based on reading the reporting file, and sending by the script a notification about the changes made on the production server, whereby a tester testing the second version of the production application is made aware of changes that have been made on the production server.

Placing data within a storage device, including: receiving, by a storage device, information describing an expected longevity of data stored on the storage device; determining, by the storage device, a location for storing the data in dependence upon the expected longevity of the data; adjusting a garbage collection schedule in dependence upon data placement; and providing, to a storage array controller, garbage collection statistics.

Fast modern interconnects may be exploited to control when garbage collection is performed on the nodes (e.g., virtual machines, such as JVMs) of a distributed system in which the individual processes communicate with each other and in which the heap memory is not shared. A garbage collection coordination mechanism (a coordinator implemented by a dedicated process on a single node or distributed across the nodes) may obtain or receive state information from each of the nodes and apply one of multiple supported garbage collection coordination policies to reduce the impact of garbage collection pauses, dependent on that information. For example, if the information indicates that a node is about to collect, the coordinator may trigger a collection on all of the other nodes (e.g., synchronizing collection pauses for batch-mode applications where throughput is important) or may steer requests to other nodes (e.g., for interactive applications where request latencies are important).