Symmetric Hash Join

	Symmetric Hash Join The symmetric hash join is a special type of hash join designed for data streams. Algorithm * For each input, create a hash table. * For each new record, hash and insert into inputs hash table. Test if input is equal to a predefined set of other inputs. * If so, output the records. See also * Data stream management system * Data stream mining Data Stream Mining (also known as stream learning) is the process of extracting knowledge structures from continuous, rapid data records. A data stream is an ordered sequence of instances that in many applications of data stream mining can be read o ... References Hashing Join algorithms {{Algorithm-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Hash Join The hash join is an example of a join algorithm and is used in the implementation of a relational database management system. All variants of hash join algorithms involve building hash tables from the tuples of one or both of the joined relations, and subsequently probing those tables so that only tuples with the same hash code need to be compared for equality in equijoins. Hash joins are typically more efficient than nested loops joins, except when the probe side of the join is very small. They require an equijoin predicate (a predicate comparing records from one table with those from the other table using a conjunction of equality operators '=' on one or more columns). Classic hash join The classic hash join algorithm for an inner join of two relations proceeds as follows: * First, prepare a hash table using the contents of one relation, ideally whichever one is smaller after applying local predicates. This relation is called the build side of the join. The hash table entries ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Data Stream In connection-oriented communication, a data stream is the transmission of a sequence of digitally encoded coherent signals to convey information. Typically, the transmitted symbols are grouped into a series of packets. Data streaming has become ubiquitous. Anything transmitted over the Internet is transmitted as a data stream. Using a mobile phone to have a conversation transmits the sound as a data stream. Formal definition In a formal way, a data stream is any ordered pair ( s, \Delta ) where: # s is a sequence of tuples and # \Delta is a sequence of positive real time intervals. Content Data Stream contains different sets of data, that depend on the chosen data format. * Attributes – each attribute of the data stream represents a certain type of data, e.g. segment / data point ID, timestamp, geodata. * Timestamp attribute helps to identify when an event occurred. * Subject ID is an encoded-by-algorithm ID, that has been extracted out of a cookie. * Raw Data inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Data Stream Management System A data stream management system (DSMS) is a computer software system to manage continuous data streams. It is similar to a database management system (DBMS), which is, however, designed for static data in conventional databases. A DBMS also offers a flexible query processing so that the information needed can be expressed using queries. However, in contrast to a DBMS, a DSMS executes a ''continuous query'' that is not only performed once, but is permanently installed. Therefore, the query is continuously executed until it is explicitly uninstalled. Since most DSMS are data-driven, a continuous query produces new results as long as new data arrive at the system. This basic concept is similar to Complex event processing so that both technologies are partially coalescing. Functional principle One important feature of a DSMS is the possibility to handle potentially infinite and rapidly changing data streams by offering flexible processing at the same time, although there are only li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Data Stream Mining Data Stream Mining (also known as stream learning) is the process of extracting knowledge structures from continuous, rapid data records. A data stream is an ordered sequence of instances that in many applications of data stream mining can be read only once or a small number of times using limited computing and storage capabilities. In many data stream mining applications, the goal is to predict the class or value of new instances in the data stream given some knowledge about the class membership or values of previous instances in the data stream. Machine learning techniques can be used to learn this prediction task from labeled examples in an automated fashion. Often, concepts from the field of incremental learning are applied to cope with structural changes, on-line learning and real-time demands. In many applications, especially operating within non-stationary environments, the distribution underlying the instances or the rules underlying their labeling may change over time, i.e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Hashing Hash, hashes, hash mark, or hashing may refer to: Substances * Hash (food), a coarse mixture of ingredients * Hash, a nickname for hashish, a cannabis product Hash mark Hash mark (sports), a marking on hockey rinks and gridiron football fields Hatch mark, a form of mathematical notation * Number sign (#), also known as the hash, hash mark, or (in American English) pound sign * Service stripe, a military and paramilitary decoration * Tally mark, a counting notation Computing * Hash function, an encoding of data into a small, fixed size; used in hash tables and cryptography * Hash table, a data structure using hash functions * Cryptographic hash function, a hash function used to authenticate message integrity * URI fragment, in computer hypertext, a string of characters that refers to a subordinate resource * Geohash, a spatial data structure which subdivides space into buckets of grid shape * Hashtag, a form of metadata often used on social networking websites * hash (Unix), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]