Abstract: Examples disclosed herein relate to a hierarchical file system. The hierarchical file system may include a first and a second virtual file referencing a stored data set. The first virtual file may include a set of first keys of a first level of specificity, with each key of the set of first keys including a record locator. The second virtual file may include a set of second keys referencing the data set and of a second level of specificity. The set of first keys within the first virtual file is searched in response to a query for data of the data set. A key from the set of second keys is accessed via the record locator from a key from the set of first keys where the data of the data set was not identified by the set of first keys.

Abstract: Examples include a system comprising a non-volatile memory, a cluster management interface, and a multi-node cluster. In some examples, the cluster management interface may monitor a system critical alert to determine if the system critical alert has been triggered. Based on the determination that it has been triggered, the cluster management interface may multicast a system failure notification. The multi-node cluster of the system has multiple nodes, each node connected to the non-volatile memory and having a processor and a processor cache. Each node of the multi-node cluster may determine if the system failure notification has been received and based on the determination that it has been received, each node may freeze execution of all processes on the process and flush the processor cache to the non-volatile memory.

Abstract: In some examples, a node of a computing system may include a failure identification engine and a failure response engine. The failure identification engine may identify a failure condition for a system function of the node and the failure response engine may store a failure indication in a shared memory to trigger takeover of the system function by a different node of the computing system.

Abstract: A data processing system includes a query progress analyzer. The database processing system comprises a receiver that receives database queries including a target query directed to a database and a query analyzer. The query analyzer is coupled to the receiver and analyzes progress status of the target query based on comparison of measured target query resource usage to resource usage predicted from a query plan of the target query and measured system resource usage.

Abstract: Examples include a system comprising a non-volatile memory, a cluster management interface, and a multi-node cluster. In some examples, the cluster management interface may monitor a system critical alert to determine if the system critical alert has been triggered. Based on the determination that it has been triggered, the cluster management interface may multicast a system failure notification. The multi-node cluster of the system has multiple nodes, each node connected to the non-volatile memory and having a processor and a processor cache. Each node of the multi-node cluster may determine if the system failure notification has been received and based on the determination that it has been received, each node may freeze execution of all processes on the process and flush the processor cache to the non-volatile memory.

Abstract: A data processing system performs query progress estimation based on processed value packets. In the illustrative data processing system, a database query processor comprises a query optimizer that creates a query plan, and a database plan executor that executes the query plan and observes intermediate result streams processed as the query plan is executed. A value packet manager anticipates value packets during query optimization, creates value packets as the intermediate result streams are processed, and compares anticipated value packets with created value packets to determine accuracy of the anticipated value packets and estimate query progress.

Abstract: Systems and methods associated with page modification are disclosed. One example method may be embodied on a non-transitory computer-readable medium storing computer-executable instructions. The instructions, when executed by a computer, may cause the computer to fetch a page to a buffer pool in a memory. The page may be fetched from at least one of a log and a backup using single page recovery. The instructions may also cause the computer to store a modification of the page to the log. The modification may be stored to the log as a log entry. The instructions may also cause the computer to evict the page from memory when the page is replaced in the buffer pool. Page writes associated with the eviction may be elided.

Abstract: A method of implementing a tree data structure comprises creating a parent and child relationship between a first node and a second node, in which the first node and second node are at the same hierarchical level of the tree data structure, and maintaining only one incoming pointer for each of the nodes in the tree data structure at all times. A tree data structure in which each node in the tree data structure has a single incoming pointer, and in which the tree data structure comprises a pointer directed to a local overflow node from a node at the same hierarchical level as the local overflow node.

Abstract: A shiftable memory supporting in-memory data structures employs built-in data shifting capability. The shiftable memory includes a memory having built-in shifting capability to shift a contiguous subset of data from a first location to a second location within the memory. The shiftable memory further includes a data structure defined on the memory to contain data comprising the contiguous subset. The built-in shifting capability of the memory to facilitate one or more of movement of the data, insertion of the data and deletion of the data within the data structure.

Abstract: A system is disclosed for managing address reflectors. In one example, the system discloses a reflector storage 108, 116, 124, 608, with a set of reflector members 304 associated with a set of reflector names 306. The system also includes a computer 100, 604 programmed with executable instructions 500, 610 which operate a set of modules. The modules includes reflector management module 106, 114, 122 which, receives a character-string from user input 104, 120, and identifies the reflector names 306 whose reflector members 304 are partially defined by the character-string.

Abstract: Approaches for structuring a plurality of page images in-memory are described in various examples of the present disclosure. In one example, a unique page identifier provided within a reference page image is identified. The unique page identifier is associated with a target page image stored in-memory. Once identified, the page identifier associated with the target page image is replaced with a location specific identifier of the target page image, wherein the location specific identifier is based on an in-memory location of the target page image.

Abstract: Systems and methods associated with latch-free searching are disclosed. One example method includes receiving a key identifying data to be retrieved from a tree-based data structure. The method also includes performing a concurrent, latch-free search of the tree-based data structure until a leaf node is reached. The method also includes validating the leaf node. The method also includes retreading a portion of the search if the leaf node fails validation.

Abstract: Disclosed herein are a system, non transitory computer-readable medium, and method for estimating database performance. A request for an estimate of data is read. The estimate is calculated based at least partially on a node located in a data structure.

Abstract: A shiftable memory supporting bimodal data storage includes a memory having built-in shifting capability to shift a contiguous subset of data stored in the memory from a first location to a second location within the memory. The shiftable memory further includes a bimodal data storage operator to operate on a data structure comprising the contiguous subset of data words and to provide in-place insertion of a data value using the built-in shifting capability.

Abstract: A data portion is evicted from a buffer, where the evicted data portion is modified from a corresponding data portion in a persistent storage. Write elision is applied to suppress writing the evicted data portion to the persistent storage. Subsequent to applying the write elision and in response to reading a version of the data portion, a redo of a modification of the read data portion is applied.

Abstract: A system, method, and non-transitory computer readable medium for providing controlled lock violation for data transactions are presented. The system includes a processor for executing a first data transaction and a second data transaction, the first and second data transactions operating on a plurality of data resources. A controlled lock violation module grants to the second transaction a conflicting lock to a data resource locked by the first transaction with a lock, the conflicting lock granted to the second transaction while the first transaction holds its lock. The controlled lock violation module can be applied to distributed transactions in a two-phase commit and to canned transactions.

Abstract: Failure of storage media containing at least a portion of a database that has been backed up to backup media is detected. In response to detecting the failure, a log that includes transactions carried out with respect to the database is analyzed. Transactions that access the database are run prior to completion of recovery of the portion of the database from the backup media. Recovery of individual pages is carried out as the individual pages are accessed by the running transactions.

Abstract: Computer-implemented and associated operating methods evaluate robustness of a query plan by measuring performance with regard to a range of runtime conditions and producing a map of relative performance of the given query plan when compared with alternative plans for a range of conditions. The computer-implemented system comprises logic that evaluates the selected query plan in comparison to multiple alternative query plans in a predetermined range of runtime conditions that include data characteristics. The logic produces a set of performance measurements and analyzes the measured performance to map performance of the selected query plan in comparison to performance of one or more alternative query plans.

Abstract: Systems and methods of using delta partitions for backup and restore are disclosed. An example method may include after a full backup, separating change information from static information. The method may also include concentrating the change information in a delta partition prior to a differential backup. The method may also include incrementally backing up only the delta partition during the differential backup.

Abstract: Computer-implemented systems and associated operating methods create and use an operator map to identify and evaluate database query plan robustness landmarks. The computer-implemented system comprises logic that creates a map evaluating performance of an implementation of a database engine operator during execution under actual operating conditions. The logic measures and maps performance for a selected range of runtime conditions including resource availability and data characteristics.