Table 1 Notation used
From: On hierarchical clustering-based approach for RDDBS design
nf | The total number of fragments |
m | The number of sites |
Q | The number of queries under consideration |
pr | The number of predicates |
CN | The number of clusters of sites |
CQ | The number of clusters of queries |
i | Fragment index, I = {1,…, n} |
j | Site index, j = {1,…, m} |
K | Query index, h = {1,…, k} |
cni | Sites’ cluster index Cni = {1, …, cn} |
cnq | Query’s cluster index Cnq = {1, …, cq} |
Ci | Storage capacity of site Si |
V | The attribute size |
Size (Fk) | Size of the kth fragment |
Sel (Qk) | The percentage rate of rows returned by the kth query |
QFMij | The frequency of the ith query over site Sj |
CCMij | The communication cost unit between cluster Ci and cluster Cj |
CMSij | The communication cost unit between site Si and site Sj, measured in “ms/byte” units, and bandwidths fall in; 64 kbps, 128 kbps and 512 kbps |
COMij | CMSij cost, if Si and Sj are at the same cluster; otherwise, CCMij cost |
LNF | The lowest number of fragments allowed at each site |
UNF | Upper number of fragments allowed at each site |
TC | The total cost of data transmission as distributed query processed |
XFkj | 1, if fragment Fk is placed in Sj; 0, otherwise |
ACvalue | ACvalue is a piled-up value that refers to the total access cost produced by each query to access its relative fragment |
FPM | Matrix in which each FPMij is 1, Fi contains Pj; 0, else |
FSM | Matrix in which each FSMij is ACvalue, Sj requires queries of Fi; 0, otherwise |
SPM | Site Predicate Matrix |
TSPM | The total cost of SPM which is grouped based on the container clusters of sites |
TCCM | Matrix of Total costs of communication between clusters |
TCSM | Matrix of Total costs of communication between sites |
QUM | Query Usage Matrix; 1, Qi required by Sj; 0, otherwise |
QDM | Query Difference Matrix, so each QDMij is the difference value between Qi and Qj |