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Data structure for hash operation and hash table storage and query method based on data structure

A technology of hash operation and data structure, which is applied in query, hash table storage, optimization design and hardware implementation of high-performance hash table, and data structure field of hash operation, which can solve problems such as low performance and reduce hash rate. The probability of conflict occurrence, the avoidance of space waste, and the effect of good uniqueness

Pending Publication Date: 2020-09-04
PLA STRATEGIC SUPPORT FORCE INFORMATION ENG UNIV PLA SSF IEU
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AI Technical Summary

Problems solved by technology

The cuckoo hash algorithm can always complete the query operation within a certain time by detecting more candidate positions, but for inserting or updating key values, it may cause low performance due to conflict handling

Method used

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  • Data structure for hash operation and hash table storage and query method based on data structure
  • Data structure for hash operation and hash table storage and query method based on data structure
  • Data structure for hash operation and hash table storage and query method based on data structure

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Embodiment Construction

[0021] In order to make the purpose, technical solution and advantages of the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and technical solutions.

[0022] For problems such as conflicts and efficiency in hash operations, the embodiment of the present invention starts from the actual application requirements of EEG identity authentication technology, see figure 1 As shown, a data structure for hash operations is provided, and the data structure for hash operations includes: d hash subtables and 2d hash functions, each hash subtable corresponds to two hash functions, Each key value obtains the corresponding candidate address through 2d hash functions, where d≥2.

[0023] Improve based on the table-building principle of cuckoo hash, establish d(d≥2) hash tables, each hash table corresponds to two hash functions, and each key value is calculated according to 2d hash ...

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Abstract

The invention belongs to the field of computer hash data structures, in particular to a data structure for hash operation and a hash table storage and query method based on the structure. In order toensure the query efficiency, a dual-port memory bank is adopted for hardware implementation, the content of two addresses of the memory bank can be read at the same time, key value comparison can be completed within the determined time, and the method is suitable for achieving efficient query in an assembly line mode. More candidate positions are provided through more hash operations, the probability of hash conflicts is reduced, the insertion, storage and updating efficiency of hash table entries is improved, dynamic change of hash table entry capacity is supported, space waste or performancereduction caused by table entry insertion operation is avoided, and the method is suitable for applications with unknown and constantly changing hash table entries. A CRC algorithm is adopted as a hash function, a hash calculation result has good uniqueness, the hash calculation result can be obtained on the basis of XOR exclusive-OR operation and a parallel pipeline implementation structure during specific implementation, and hardware design implementation is facilitated.

Description

technical field [0001] The invention belongs to the field of computer hash data structures, in particular to a data structure for hash operations and a hash table storage and query method based on the structure, so as to be suitable for optimal design and hardware realization of high-performance hash tables. Background technique [0002] Hash table (Hash table) is the key data structure for network message flow management. The hash table is based on message keywords. Through hash function operation, you can access the index information corresponding to the stored key value, which greatly improves the search efficiency. The hash function is essentially a transformation that maps elements from a larger input space to a smaller index space. Therefore, two or more keywords may be mapped to the same position. In the hash table, this The situation is called an address collision. When a conflict occurs, it will affect the insertion efficiency of the hash table. Therefore, an eff...

Claims

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Application Information

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IPC IPC(8): G06F16/22
CPCG06F16/2255G06F16/2282
Inventor 刘冬培刘勤让吕平沈剑良宋克陈艇李沛杰汤先拓张丽张文建
Owner PLA STRATEGIC SUPPORT FORCE INFORMATION ENG UNIV PLA SSF IEU
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