/**
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
licenses@blazegraph.com
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* Created on Nov 27, 2011
*/
package com.bigdata.rdf.sparql.ast.hints;
import com.bigdata.bop.engine.NativeHeapStandloneChunkHandler;
import com.bigdata.bop.join.HTreeHashJoinUtility;
import com.bigdata.bop.join.IHashJoinUtility;
import com.bigdata.bop.join.JVMHashJoinUtility;
import com.bigdata.bop.join.SolutionSetHashJoinOp;
import com.bigdata.htree.HTree;
import com.bigdata.rdf.sparql.ast.ASTBase;
import com.bigdata.rdf.sparql.ast.QueryHints;
import com.bigdata.rdf.sparql.ast.QueryRoot;
import com.bigdata.rdf.sparql.ast.eval.AST2BOpContext;
/**
* Query hint for turning analytic query on/off.
* <p>
* TODO Allow this to be specified for each hash index build rather than just
* globally for the query execution context. The primary consumer of hash
* indices is the {@link SolutionSetHashJoinOp}. That operator implementation
* identical for both JVM and {@link HTree} based hash joins. Therefore, we
* could make the decision about whether to use the {@link JVMHashJoinUtility}
* or the {@link HTreeHashJoinUtility} when building the hash index by
* annotating that operator and then let the {@link SolutionSetHashJoinOp}
* handle the hash join by delegating to the appropriate
* {@link IHashJoinUtility} implementation.
*/
final class AnalyticQueryHint extends AbstractBooleanQueryHint {
protected AnalyticQueryHint() {
super(QueryHints.ANALYTIC, QueryHints.DEFAULT_ANALYTIC);
}
@Override
public void handle(final AST2BOpContext context, final QueryRoot queryRoot,
final QueryHintScope scope, final ASTBase op, final Boolean value) {
switch (scope) {
case Query:
context.nativeHashJoins = value;
context.nativeDistinctSolutions = value;
context.nativeDistinctSPO = value;
context.queryEngineChunkHandler = NativeHeapStandloneChunkHandler.NATIVE_HEAP_INSTANCE;
return;
}
throw new QueryHintException(scope, op, getName(), value);
}
}