Hybrid hash tables
First Claim
1. A computer-implemented method for inserting a new entry in a hash table system in a data storage system, the method comprising:
- providing the hash table system having a first hash table and a second hash table;
computing a first index for the new entry, the first index corresponding to a first element in the first hash table;
computing a second index for the new entry, the second index corresponding to a second element in the second hash table;
inserting a first entry corresponding to the new entry into the first element in the first hash table; and
when the first hash table reaches a threshold load factor, flushing the first entry from the first hash table,wherein flushing comprises inserting a value associated with the new entry into the second element in the second hash table, and removing the first entry from the first element in the first hash table.
2 Assignments
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Accused Products
Abstract
A hash table system having a first hash table and a second hash table is provided. The first hash table may be in-memory and the second hash table may be on-disk. Inserting an entry to the hash table system comprises inserting the entry into the first hash table, and, when the first hash table reaches a threshold load factor, flushing entries into the second hash table. Flushing the first hash table into the second hash table may comprise sequentially flushing the first hash table segments into corresponding second hash table segments. When looking up a key/value pair corresponding to a selected key in the hash table system, the system checks both the first and second hash tables for values corresponding to the selected key. The first and second hash tables may be divided into hash table segments and collision policies may be implemented within the hash table segments.
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Citations
28 Claims
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1. A computer-implemented method for inserting a new entry in a hash table system in a data storage system, the method comprising:
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providing the hash table system having a first hash table and a second hash table; computing a first index for the new entry, the first index corresponding to a first element in the first hash table; computing a second index for the new entry, the second index corresponding to a second element in the second hash table; inserting a first entry corresponding to the new entry into the first element in the first hash table; and when the first hash table reaches a threshold load factor, flushing the first entry from the first hash table, wherein flushing comprises inserting a value associated with the new entry into the second element in the second hash table, and removing the first entry from the first element in the first hash table. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A data storage system comprising:
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a hash table system comprising a first hash table and a second hash table; an insertion module for inserting a new entry in the hash table system, wherein inserting comprises computing a first index for the new entry, the first index corresponding to a first element in the first hash table; computing a second index for the new entry, the second index corresponding to a second element in the second hash table; inserting a first entry corresponding to the new entry into the first element in the first hash table; and an entry flushing module for flushing the first entry from the first hash table when the first hash table reaches a threshold load factor, wherein flushing comprises inserting a value associated with the new entry into the second element in the second hash table, and removing the first entry from the first element in the first hash table. - View Dependent Claims (18, 19, 20, 21, 22)
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23. A computer program product comprising a non-transitory computer usable medium having computer-executable instructions that control a computer to perform a method for inserting a new entry in a hash table system, the method comprising the computer-implemented steps of:
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providing the hash table system comprising a first hash table and a second hash table; computing a first index for the new entry, the first index corresponding to a first element in the first hash table; computing a second index for the new entry, the second index corresponding to a second element in the second hash table; inserting a first entry corresponding to the new entry into the first element in the first hash table; and when the first hash table reaches a threshold load factor, flushing the first entry from the first hash table, wherein flushing comprises inserting a value associated with the new entry into the second element in the second hash table, and removing the first entry from the first element in the first hash table. - View Dependent Claims (24, 25, 26, 27, 28)
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Specification