… a semijoin operator is useful for decreasing I/O and transmission times in a
multiprocessor system, we present and compare two equi-semijoin algorithms and one non-equi-semijoin …

… and RI is called the reducee of the semi-join. To simplify the notation, we use R, + RI to
mean a semi-join from R, to RI in the case the semi-join attribute does not have to be specified. …

… semijoin, and join processing algorithms based on a new cluster-based join index. We focus
on three new R-join/R-semijoin … semijoin discussed in this work is different from the semijoin …

… by which S is reduced by the semi-join. The SDD-I algorithm uses a … have provided a
hardware semi-join instruction that they … In this paper we examine the question of which semi-join …

… semi-join operator in improving the performance of joins by replacing the join of two relations
by the join of their semi-join … In the following, we assume that a semi-join or join operation is …

… We shall call any sequence of semi-join operations a program (or strategy). Our problem
then is to study semi-join programs that help solve relational queries in an "optimal" fashion …

… Using the semi-join operators we can rewrite the above expression … semi-join has also been
studied in the context of the multiset relational algebra [23]. This focus on using the semi-join …

A combination of join and semijoin operations is applied to minimize the communication
cost for distributed query processing. A formula is developed to estimate the cardinality of a …

… Thus, as in most prior work 1] 3], we assume in this paper the cardinality of a non-semijoin
attribute remains the same after a semijoin operation to simplify our discussion. In addition, to …

… a relational operator called a semijoin. A semijoin is "half ofa join’’2" the semijoin of relation
R1 by … In other words, the semijoin retrieves all tuples of R that join with anytuple of R2. While …