or classroom use is ranted without fee provided that copies are not made. 7 ... software may be easily modified to implement a spatial hash-join, facilitating ... can be easily estimated. A spatial join following this paradigm may also lead ...... result- ing method is simple in design and efficient when im- plemented. (see. Section.
Spatial Ming-Ling
Lo
Department University
Hash-Joins* Chinya
of EECS
Ann
mingling@eecs.
University
Arbor
Arbor,
MI 48109
joins,
and
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[8, 9] being
excellent are
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for
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is
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joins
the
efficient
function
in
our
247
a spatial
hash-
counterpart, our
method
a variety
of data
method
partitions
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partition
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join
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method.
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refinement
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propose methods.
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to
function
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framework,
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to
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Introduction
performance,
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methods
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Further,
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method
dataset,
replicate
in other
algorithms
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MI 48109
besides
software
estimated.
joins. show
join
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indices.
experiments
current
sampling
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function
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Arbor,
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Ann
Arbor
ravi@eecs. umich.edu
The how to apply
of EECS
of Michigan-Ann
1301 Beal Avenue,
umich .edu
Abstract We examine
Ravishankar
Department
of Michigan–Ann
1301 Beal Avenue,
V.
method
by
wide
are given highly
are dynamically
pre-computed
our spatial
indices.
spatial join
margins,
hash-join algorithms even
pre-computed competitive generated
when
indices. both and
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This
paper
discusses in
is
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organized
related
work.
the
hash-join
framework Section
spatial
for
implementation. in
and
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7.
results
our
of
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———4 —
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of
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1:
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9].
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and Schilling
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10, 14], and
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tation.
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based
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[21]
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[8, 9] being
clude
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dataset,
Work
methods
sumed
A simple one
dashed
3.1 Previous
Bucket2
are
respect
assignment to
a join
predicate.
complicated.
Unfortunately,
248
spatial
do not
always
define
such
equivalence
to guarantee buckets
a coherent
with
respect
we cannot
divide
n groups,
and
in any We
this
difficulty
the
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through this
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inner
using
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and
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Single
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(12, 22), (11, 21) and Single
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The
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A bucket
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function
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buckets. appear
built.
pairs.
Hybrids
be appropriate
249
and
endure
schedule
the
multiple-assignment we need With
may
22 (see Figure only
this
2(b)).
match
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buffer
However,
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X
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twice. is particularly
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The
complicates
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21 and
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example, buckets
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12 is needed
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trees
We
not
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indices
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We believe
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2 overlaps bucket
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Figure
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Our
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Bu&ket Bye$et Bu;fket E3y~t .——. = J; —_. — 1 J I —.
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Discussion
assignment
show
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Acknowledgment:
system
their
[25],
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The
Our
focus
has
P. Kriegel
PBSM
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partition
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implementation
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used
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have
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are efficient
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functions
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paper
tree
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but
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of
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design
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files
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in
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4.3. 1).
We the
area,
[1]
The
and
Identical are
used
for
like to thank
Dr. T. Brinkhoff,
B. Seeger for generously
used in our experiment
with
real-life
Prof.
H.-
providing
the
data.
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