hash table

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hash table

hash table

A lookup table that is designed to efficiently store non-contiguous keys (account numbers, part numbers, etc.) that may have wide gaps in their alphabetic and numeric sequences.

Hash tables are created by using a hashing function (algorithm) to hash the keys into hash buckets. Each bucket is a list of key value pairs. Since different keys may hash to the same bucket, the goal of hash table design is to spread out the key-value pairs evenly with each bucket containing as few key-value pairs as possible. When an item is looked up, its key is hashed to find the appropriate bucket. Then, the bucket is searched for the right key-value pair.

If access to the values is desired other than through the keys, an indexing system can be built on top of a hash table. Such user-level search engines can be made to handle imprecise queries and misspellings. See key-value pair and DHT.


A Hash Table
When an item is looked up, its key is hashed into a hash value that becomes the index into the bucket. Then, the bucket is searched for the right key-value pair.
References in periodicals archive ?
Yang Xu et al (2014) proposed multi-match packet classification rules formation algorithm with the help of distributed and pipelined hash tables and avoided the use of Ternary Content Addressable Memory and signature tree which consumed large amount of memory and time.
SHJ can produce a result before reading either input relation entirely, however, the algorithm keeps both the hash tables, required for each input, in memory.
After a brief introduction to Java, it covers algorithm analysis, integer stacks, generic stacks, queues, lists, recursion, trees, binary search trees, heaps, and hash tables.
Our approach, based on Distributed Hash Tables, allows complex queries to the system by means of complex multimedia metadata indexing.
You can run Proactive Password Auditor(TM) in the background to generate and use pre-computed hash tables that will allow you to find most passwords in minutes instead of days or weeks;
The result is a system that's not only useful for sharing data between applications, but also for replacing traditional data structures such as hash tables, lists and arrays, and it can even export its data to disk if required.
Before calculating the kernel values between documents, we first convert all documents into the form of hash tables as the Figure 1.
Other topics covered include self-stabilization in preference-based networks, the design and evaluation of techniques for route diversity in distributed hash tables, and the effect of virtual media on business usage of peer-to-peer.
StreamBase achieves processing speeds in excess of 140,000 messages/second by processing data on-the-fly without the store-and-query overhead imposed by traditional systems -- StreamBase applications run in a single operating system process which provides high throughput and minimal latency, and eliminates the need for process switching between multiple systems such as application servers, messaging systems, and storage -- StreamBase's flexible integrated storage lets applications maintain state using in-memory hash tables, local disk, or remote databases via ODBC if needed StreamSQL
Our Grid DBMS PORDaS is based on distributed hash tables (DHT).
Topics include software aging and rejuvenation in a SOAP-based server, congestion control for distributed hash tables, video-on- demand equipment allocation, and analysis models for blind search in unstructured overlays.
Most of the existing Data Lookup Systems employ lookup protocols that are based on the Distributed Hash Tables (DHTs).