156 results about "B-tree" patented technology

A data structure, added to a modified form of the B^link-tree data structure, tracks delete states for nodes. The index delete state (D_X) indicates whether it is safe to directly access an index node without re-traversing the B-tree. The D_X state is maintained globally, outside of the tree structure. The data delete state (D_D) indicates whether it is safe to post an index term for a new leaf node. A D_D state is maintained in each level 1 node for its leaf nodes. Delete states indicate whether a specific node has not been deleted, or whether it may have been deleted. Delete states are used to remove the necessity for atomic node splits and chains of latches for deletes, while not requiring retraversal. This property of not requiring a retraversal is exploited to simplify the tree modification operations.

The invention relates to a parallel data processing method based on a distributed structure. The storing comprises steps as follows: (1) a data master key value is extracted from master nodes according to types of master key values, directed slave nodes distributed by data are determined according to data attribute values and a section comparison result in the master nodes, and simultaneously, a global keyword B+ tree index is established; (2), the data are distributed to the slave nodes corresponding to the master key values according to the global keyword B+ tree index on the basis of a share-nothing principle; and (3), the slave nodes receive a data distributing request, and the data are stored in child nodes locally on the basis of the share-nothing principle. According to the method, an effective index mechanism is combined, and the storage and management efficiency of system data is improved; on one hand, the reasonable data distribution is guaranteed, the storage throughput of the slave nodes is reduced, the local query performance is improved, and the system flexibility is guaranteed by utilizing high expandability of the slave nodes; and on the other hands, local transcript safety is guaranteed through local duplication of multiple transcripts.

Portions of a B-tree index in a database are locked for concurrency control. In one example, hierarchical lock modes are provided that permit locking a key, a gap between the key and the next key, and a combination of the key and the gap. In another example, key range locking may be applied to the B-tree index using locks on separator keys of index nodes. In another example, key range locking may be applied to the B-tree index using locks on key prefixes.

A solid state disk (SSD) caches disk-based volumes in a heterogeneous storage system, improving the overall storage-system performance. The hottest data blocks are identified based on two factors: the frequency of access, and temporal locality. Temporal locality is computed using a logarithmic system time. IO latency is reduced by migrating these hottest data blocks from hard-disk-based volumes to the solid-state flash-memory disks. Some dedicated mapping metadata and a novel top-K B-tree structure are used to index the blocks. Data blocks are ranked by awarding a higher current value for recent accesses, but also by the frequency of accesses. A non-trivial value for accesses in the past is retained by accumulating the two factors over many time spans expressed as a logarithmic system time. Having two factors, access frequency and the logarithmic system time, provides for a more balanced caching system.

The creation of multiple recoverable units within a database allows a database partition to be reconstructed during maintenance and disaster recovery operations. A method of creating a recovery unit includes partitioning a database into at least two recovery units. A primary catalog of metadata relating to the logical elements of a database such as tables, indexes, and file groups is created. A secondary catalog of metadata relating to the physical elements of a database such as pages, files, B-Trees, and log streams is created for each recovery unit. The primary and secondary metadata catalogs are linked such that only one log stream is associated with any one recovery unit. A single recovery unit may then be exercised to perform recovery or maintenance operations while the remaining recovery units of the database remain online.

A storage mamagement method of embedded database,includes that: (1) the storage strategy of data in the memory is that: if logic structure accords with physical structure, the structure is into a divided system area, a main storage database area, a user working area, a log area and a preformed area; the storage strategy of data in the external memory is that: logic structure is divided into a database table, a segment and a database block; physical structure includes a physical file and a physical block; (2) the physical file organization of database is that: a data dictionary is placed at the heading, a user table since then; (3) the memory management of data dictionaryin the external memory is that: the described information of physical file is stored in the file header, denotative definition kind and attribute definition kind adopt a three section type storage form; data dictionary adopt a page type memory management method in the memory; (4) a permanent memory data is stored using T tree and a a permanent external memory data is stored using B+ tree; data and its index are managed using a extended segment memory management method. The invention improves the utilization rate of memory space, and accelerate the speed of data to access.

An optimistic, latch-free index traversal (''OLFIT') concurrency control scheme is disclosed for an index structure for managing a database system. In each node of an index tree, the OLFIT shceme maintains a latch, a version number, and a link to the next node at the same level of the index tree. Index traversal involves consistent node read operations starting from the root. To ensure the consistency of node read operations without latching, every node update operation first obtains a latch and increments the version number after update of the node contents. Every node read operation begins with reading the version number into a register and ends with verifying if the current version number is consistent with the register-stored version number. If they are the same, the read operation is consistent. Otherwise, the node read is retried until the verification succeeds. The concurrency control scheme of the present invention is applicable to many index structures such as the B+-tree and the CSB+-tree.

Methods of updating b-tree data structures (e.g., b*tree data structure) using search key insertion and deletion operations proceed from respective known states (e.g., respective canonical forms). These insertion operations include inserting a first search key into the b-tree by reconfiguring (e.g., pre-processing) a plurality of sibling nodes of the b-tree into a predetermined overloaded form having a shape that is independent of a value of the first search key to be inserted therein. An operation is then performed to split the sibling nodes by redistributing the first and other search keys among an expanded plurality of the sibling nodes. These insertion operations use a process that trades off possibly performing additional memory accesses (e.g., to shift search keys (and/or handles or pointers) to the predetermined overloaded form) for the certainty that the same key movements are ultimately performed during operations to split sibling nodes.

The invention discloses a full flash system metadata placing method. The full flash system metadata placing method comprises the following steps: confirming a node to be placed in a target B+ tree when the metadata stored in the memory reaches a preset placing threshold of the metadata; placing the node to be placed in the form of B+ tree; and recording the placing address of the node to be placed, wherein the node in the B+ tree is the node for storing the metadata. By means of the technical scheme provided by the embodiment of the invention, the nodes to be placed with the metadata are placed sequentially, therefore, the efficiency of metadata reading is greatly improved while ensuring the efficiency of placing, the performance of the full flash system is improved, and the user experience is improved. The invention also discloses a full flash system metadata placing device and equipment and a storage medium, which have the corresponding technical effects.

A method and apparatus for improving search performance in databases organized in B Tree or B+ Tree format has an automatic determination and switching between two methods. It also searches to the end of a current leaf page even if a current value for all key parameters has been fulfilled in the search prior to reaching the end of the current leaf page. Swinging across and thus skipping leaf pages to fetch a next leaf page (trapeze fetching or swinging) is activated only either initially or where a B Tree search has resulted in a skipping of leaf pages previously in a search. User interference with the automatic selection of search type between next sequential leaf or trapeze type is not provided for and not allowed.

A pipelined search engine device, such as a longest prefix match (LPM) search engine device, includes a hierarchical memory and a pipelined tree maintenance engine therein. The hierarchical memory is configured to store a b−tree of search prefixes (and possibly span prefix masks) at multiple levels therein. The pipelined tree maintenance engine, which is embedded within the search engine device, includes a plurality of node maintenance sub-engines that are distributed with the multiple levels of the hierarchical memory. The search engine device may also include pipeline control and search logic that is distributed with the multiple levels of the hierarchical memory.