نتایج جستجو برای: join space

تعداد نتایج: 509255  

The original aim of this paper is to construct a graph associated to a vector space. By inspiration of the classical definition for the Cayley graph related to a group we define Cayley graph of a vector space. The vector space Cayley graph ${rm Cay(mathcal{V},S)}$ is a graph with the vertex set the whole vectors of the vector space $mathcal{V}$ and two vectors $v_1,v_2$ join by an edge whenever...

2003
Panayiotis Tsaparas Themis Palpanas Yannis Kotidis Nick Koudas Divesh Srivastava

A plethora of data sources contain data entities that could be ordered according to a variety of attributes associated with the entities. Such orderings result effectively in a ranking of the entities according to the values in the attribute domain. Commonly, users correlate such sources for query processing purposes through join operations. In query processing, it is desirable to incorporate u...

2004
Benjamin James McMahan Devika S. Subramanian

The join operation, which combines tuples from multiple relations, is the most fundamental and, typically, the most expensive operation in database queries. The standard approach to join-query optimization is cost based, which requires developing a cost model, assigning an estimated cost to each query-processing plan, and searching in the space of all plans for a plan of minimal cost. But as th...

2004
Anagh Lal Berthe Y. Choueiry

Constraint Processing and Database techniques overlap significantly. We discuss here the application of a constraint satisfaction technique, called dynamic bundling, to databases. We model the join query computation as a Constraint Satisfaction Problem (CSP) and solve it by search using dynamic bundling. First, we introduce a sort-based technique for computing dynamic bundling. Then, we describ...

Journal: :PVLDB 2017
Erkang Zhu Yeye He Surajit Chaudhuri

Traditional equi-join relies solely on string equality comparisons to perform joins. However, in scenarios such as adhoc data analysis in spreadsheets, users increasingly need to join tables whose join-columns are from the same semantic domain but use different textual representations, for which transformations are needed before equi-join can be performed. We developed Auto-Join, a system that ...

Journal: :PVLDB 2014
Rafi Ahmed Rajkumar Sen Meikel Pöss Sunil Chakkappen

Many workloads for analytical processing in commercial RDBMSs are dominated by snowstorm queries, which are characterized by references to multiple large fact tables and their associated smaller dimension tables. This paper describes a technique for bushy join tree optimization for snowstorm queries in Oracle database system. This technique generates bushy join trees containing subtrees that pr...

1998
Shashi Shekhar Chang-tien Lu Sivakumar Ravada Sanjay Chawla

A Join Index is a data structure that optimizes the join query processing in spatial databases. Join indices use pre-computation techniques to speed up online query processing and are useful for applications which require low update rates. The cost of spatial join computation using a join-index with limited buuer space depends primarily on the page access sequence used to fetch the pages of the...

1995
Michael Steinbrunn Klaus Peithner Guido Moerkotte Alfons Kemper

The bypass technique, which was formerly restricted to selections only KMPS94], is extended to join operations. Analogous to the selection case, the join operator may generate two output streams|the join result and its complement|whose subsequent operator sequence is optimized individually. By extending the bypass technique to joins, several problems have to be solved. (1) An algorithm for exha...

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