/**
* Copyright (c) 2013, Institute of Information Systems (Sven Groppe and contributors of LUPOSDATE), University of Luebeck
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
* following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice, this list of conditions and the following
* disclaimer.
* - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
* following disclaimer in the documentation and/or other materials provided with the distribution.
* - Neither the name of the University of Luebeck nor the names of its contributors may be used to endorse or promote
* products derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package lupos.optimizations.logical.rules.parallel;
import java.util.Collection;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import lupos.engine.operators.BasicOperator;
import lupos.engine.operators.Operator;
import lupos.engine.operators.OperatorIDTuple;
import lupos.engine.operators.messages.BoundVariablesMessage;
import lupos.engine.operators.multiinput.join.Join;
import lupos.engine.operators.multiinput.join.MergeJoinWithoutSorting;
import lupos.engine.operators.multiinput.optional.MergeWithoutSortingOptional;
import lupos.engine.operators.singleinput.parallel.ParallelOperand;
import lupos.engine.operators.singleinput.parallel.QueryResultInBlocks;
import lupos.misc.Tuple;
import lupos.optimizations.logical.rules.Rule;
/**
* Implements a graph transformation which inserts a {@link ParallelOperand}
* between each {@link Join} operator and its arguments, effectively evaluating
* in a separate thread and thus distributing it across possibly multiple
* processors.
*
* @see ParallelOperand
*/
public class RuleJoinWithParallelOperands extends Rule {
protected static boolean BLOCKWISE = false;
public static boolean isBLOCKWISE() {
return BLOCKWISE;
}
public static void setBLOCKWISE(final boolean blockwise) {
BLOCKWISE = blockwise;
}
@Override
protected void init() {
final Operator a = new Join();
subGraphMap = new HashMap<BasicOperator, String>();
subGraphMap.put(a, "join");
startNode = a;
}
@Override
protected boolean checkPrecondition(final Map<String, BasicOperator> mso) {
final BasicOperator join = mso.get("join");
if (isBLOCKWISE()
&& (join instanceof MergeJoinWithoutSorting || join instanceof MergeWithoutSortingOptional)) {
// blockwise does not work for merge joins/optionals!
return false;
} else
return true;
}
@Override
protected Tuple<Collection<BasicOperator>, Collection<BasicOperator>> transformOperatorGraph(
final Map<String, BasicOperator> mso,
final BasicOperator rootOperator) {
final Collection<BasicOperator> deleted = new LinkedList<BasicOperator>();
final Collection<BasicOperator> added = new LinkedList<BasicOperator>();
OperatorIDTuple tuple;
final BasicOperator join = mso.get("join");
final List<BasicOperator> pre = join.getPrecedingOperators();
join.setPrecedingOperators(new LinkedList<BasicOperator>());
for (final BasicOperator op : pre) {
if (op instanceof ParallelOperand
|| op instanceof QueryResultInBlocks) {
join.addPrecedingOperator(op);
continue;
}
final Operator par = new ParallelOperand();
par.addPrecedingOperator(op);
added.add(par);
final Operator maybequeryresultinblocks;
if (isBLOCKWISE()) {
maybequeryresultinblocks = new QueryResultInBlocks();
added.add(maybequeryresultinblocks);
par.setSucceedingOperator(new OperatorIDTuple(
maybequeryresultinblocks, 0));
maybequeryresultinblocks.addPrecedingOperator(par);
} else {
maybequeryresultinblocks = par;
}
tuple = op.getOperatorIDTuple(join);
op.replaceOperatorIDTuple(tuple, new OperatorIDTuple(par, 0));
join.addPrecedingOperator(maybequeryresultinblocks);
maybequeryresultinblocks.addSucceedingOperator(new OperatorIDTuple(
join, tuple.getId()));
}
rootOperator.detectCycles();
rootOperator.sendMessage(new BoundVariablesMessage());
if (deleted.size() > 0 || added.size() > 0)
return new Tuple<Collection<BasicOperator>, Collection<BasicOperator>>(
added, deleted);
else
return null;
}
@Override
public String getName() {
return "JoinWithParallelOperands";
}
}