Method for organizing and accessing memory database index with high performance

Abstract

The invention discloses a method for organizing and accessing memory database indexes with high performance. The method comprises the following steps of: firstly, organizing an overall index table structure in stages; then, distributing a continuous virtual address space for each stage of bucket chain table in the virtual address space of a system; mapping each bucket chain table to a corresponding virtual address space; finally, organizing indexes and data in each stage of index structure by using a chain table manner, wherein each item in the chain table is a bucket organization, attribute information of the bucket organization, a pointer pointing to a next bucket organization and index entry information are stored in each bucket organization. According to a structure for organizing the database indexes provided by the invention, data are not needed to sort when being inserted or deleted; elements in a VAB (Virtual Address Bucket) are stored disorderly, data can be identified through a bitmap; different from the mode of a tree structure, the elements are not needed to sort when a datum is inserted or deleted once in order to keep the orderliness of inner elements, thus the times of frequently writing a NVM (Non-Volatile Memory) is reduced.

Description

technical field [0001] The invention relates to the database field, in particular to a high-performance memory database index organization and access method. Background technique [0002] With the development of computer hardware technology, the price of memory continues to decrease, and the memory capacity is getting larger and larger. It is completely feasible to store all or part of the data in the database into the memory. However, traditional DRAM memory cannot retain data after power failure, so it does not have a data storage function. [0003] In recent years, a new type of memory, non-volatile memory (NVM), has emerged. The main features of this memory are: the data stored in NVM will not be lost due to power failure or system crash, its storage capacity can be close to that of disk, and NVM has a read and write speed close to that of DRAM. In addition, non-volatile memory also has many advantages such as high density, low power consumption, and radiation resistan...

AI Technical Summary

Problems solved by technology

The process of adjusting the position will generate a large number of NVM write operations

[0016] (2) The insertion and deletion operation will not only cause the node to update the information to generate the operation of writing NVM, but also affect other nodes

The process of changing information can generate a lot of write operations

[0017] (3) During range search, B+Tree needs to access and search leaf nodes one by one, which will significantly reduce the performance of B+Tree

[0018] (4) In memory, in order to improve the cache hit rate, the nodes are relatively small, so the height of the tree is very high, which will cause B+Tree to frequently adjust the structure of the tree

[0019] Whether it is a traditional B+Tree or T-tree tree structure, in order to maintain the internal order of its nodes and the balance of the tree, frequent adjustments need to be made, resulting in a large number of NVM write operations and reducing its lifespan

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