org.apache.hadoop.hive.ql.optimizer.index.RewriteCanApplyProcFactory Maven / Gradle / Ivy
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* distributed with this work for additional information
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* to you under the Apache License, Version 2.0 (the
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* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.hadoop.hive.ql.optimizer.index;
import org.apache.hadoop.hive.ql.exec.GroupByOperator;
import org.apache.hadoop.hive.ql.exec.Operator;
import org.apache.hadoop.hive.ql.exec.SelectOperator;
import org.apache.hadoop.hive.ql.exec.TableScanOperator;
import org.apache.hadoop.hive.ql.lib.Node;
import org.apache.hadoop.hive.ql.lib.NodeProcessor;
import org.apache.hadoop.hive.ql.lib.NodeProcessorCtx;
import org.apache.hadoop.hive.ql.parse.SemanticException;
import org.apache.hadoop.hive.ql.plan.AggregationDesc;
import org.apache.hadoop.hive.ql.plan.ExprNodeColumnDesc;
import org.apache.hadoop.hive.ql.plan.ExprNodeDesc;
import org.apache.hadoop.hive.ql.plan.ExprNodeDescUtils;
import org.apache.hadoop.hive.ql.plan.GroupByDesc;
import org.apache.hadoop.hive.ql.plan.OperatorDesc;
import java.util.ArrayList;
import java.util.List;
import java.util.Stack;
/**
* Factory of methods used by {@link RewriteGBUsingIndex}
* to determine if the rewrite optimization can be applied to the input query.
*
*/
public final class RewriteCanApplyProcFactory {
public static CheckTableScanProc canApplyOnTableScanOperator(TableScanOperator topOp) {
return new CheckTableScanProc();
}
private static class CheckTableScanProc implements NodeProcessor {
public CheckTableScanProc() {
}
public Object process(Node nd, Stack stack, NodeProcessorCtx ctx, Object... nodeOutputs)
throws SemanticException {
RewriteCanApplyCtx canApplyCtx = (RewriteCanApplyCtx) ctx;
for (Node node : stack) {
// For table scan operator,
// check ReferencedColumns to make sure that only the index column is
// selected for the following operators.
if (node instanceof TableScanOperator) {
TableScanOperator ts = (TableScanOperator) node;
canApplyCtx.setTableScanOperator(ts);
List selectColumns = ts.getConf().getReferencedColumns();
if (selectColumns == null || selectColumns.size() != 1) {
canApplyCtx.setSelClauseColsFetchException(true);
return null;
} else {
canApplyCtx.setIndexKey(selectColumns.get(0));
}
} else if (node instanceof SelectOperator) {
// For select operators in the stack, we just add them
if (canApplyCtx.getSelectOperators() == null) {
canApplyCtx.setSelectOperators(new ArrayList());
}
canApplyCtx.getSelectOperators().add((SelectOperator) node);
} else if (node instanceof GroupByOperator) {
if (canApplyCtx.getGroupByOperators() == null) {
canApplyCtx.setGroupByOperators(new ArrayList());
}
// According to the pre-order,
// the first GroupbyOperator is the one before RS
// and the second one is the one after RS
GroupByOperator operator = (GroupByOperator) node;
canApplyCtx.getGroupByOperators().add(operator);
if (!canApplyCtx.isQueryHasGroupBy()) {
canApplyCtx.setQueryHasGroupBy(true);
GroupByDesc conf = operator.getConf();
List aggrList = conf.getAggregators();
if (aggrList == null || aggrList.size() != 1
|| !("count".equals(aggrList.get(0).getGenericUDAFName()))) {
// In the current implementation, we make sure that only count is
// in the function
canApplyCtx.setAggFuncIsNotCount(true);
return null;
} else {
List para = aggrList.get(0).getParameters();
if (para == null || para.size() == 0 || para.size() > 1) {
canApplyCtx.setAggParameterException(true);
return null;
} else {
ExprNodeDesc expr = ExprNodeDescUtils.backtrack(para.get(0), operator,
(Operator) stack.get(0));
if (!(expr instanceof ExprNodeColumnDesc)) {
canApplyCtx.setAggParameterException(true);
return null;
}
}
}
}
}
}
return null;
}
}
}