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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.drill.exec.planner.logical;
import java.io.IOException;
import java.util.List;
import org.apache.drill.common.JSONOptions;
import org.apache.drill.common.exceptions.DrillRuntimeException;
import org.apache.drill.common.expression.SchemaPath;
import org.apache.drill.common.logical.data.LogicalOperator;
import org.apache.drill.common.logical.data.Scan;
import org.apache.drill.exec.physical.base.AbstractGroupScan;
import org.apache.drill.exec.physical.base.GroupScan;
import org.apache.drill.exec.physical.base.ScanStats;
import org.apache.drill.exec.planner.common.DrillScanRelBase;
import org.apache.drill.exec.planner.cost.DrillCostBase.DrillCostFactory;
import org.apache.drill.exec.planner.physical.PrelUtil;
import org.apache.drill.exec.planner.torel.ConversionContext;
import org.eigenbase.rel.RelWriter;
import org.eigenbase.relopt.RelOptCluster;
import org.eigenbase.relopt.RelOptCost;
import org.eigenbase.relopt.RelOptPlanner;
import org.eigenbase.relopt.RelOptTable;
import org.eigenbase.relopt.RelTraitSet;
import org.eigenbase.reltype.RelDataType;
import com.google.common.base.Preconditions;
import com.google.common.base.Predicate;
import com.google.common.collect.Iterables;
/**
* GroupScan of a Drill table.
*/
public class DrillScanRel extends DrillScanRelBase implements DrillRel {
private final static int STAR_COLUMN_COST = 10000;
final private RelDataType rowType;
private GroupScan groupScan;
private List<SchemaPath> columns;
/** Creates a DrillScan. */
public DrillScanRel(RelOptCluster cluster, RelTraitSet traits,
RelOptTable table) {
// By default, scan does not support project pushdown.
// Decision whether push projects into scan will be made solely in DrillPushProjIntoScanRule.
this(cluster, traits, table, table.getRowType(), AbstractGroupScan.ALL_COLUMNS);
}
/** Creates a DrillScan. */
public DrillScanRel(RelOptCluster cluster, RelTraitSet traits,
RelOptTable table, RelDataType rowType, List<SchemaPath> columns) {
super(DRILL_LOGICAL, cluster, traits, table);
this.rowType = rowType;
this.columns = columns == null || columns.size() == 0 ? GroupScan.ALL_COLUMNS : columns;
try {
this.groupScan = drillTable.getGroupScan().clone(this.columns);
} catch (IOException e) {
throw new DrillRuntimeException("Failure creating scan.", e);
}
}
/** Creates a DrillScanRel for a particular GroupScan */
public DrillScanRel(RelOptCluster cluster, RelTraitSet traits,
RelOptTable table, GroupScan groupScan, RelDataType rowType, List<SchemaPath> columns) {
super(DRILL_LOGICAL, cluster, traits, table);
this.rowType = rowType;
this.columns = columns;
this.groupScan = groupScan;
}
//
// private static GroupScan getCopy(GroupScan scan){
// try {
// return (GroupScan) scan.getNewWithChildren((List<PhysicalOperator>) (Object) Collections.emptyList());
// } catch (ExecutionSetupException e) {
// throw new DrillRuntimeException("Unexpected failure while coping node.", e);
// }
// }
public List<SchemaPath> getColumns() {
return this.columns;
}
@Override
public LogicalOperator implement(DrillImplementor implementor) {
Scan.Builder builder = Scan.builder();
builder.storageEngine(drillTable.getStorageEngineName());
builder.selection(new JSONOptions(drillTable.getSelection()));
implementor.registerSource(drillTable);
return builder.build();
}
public static DrillScanRel convert(Scan scan, ConversionContext context) {
return new DrillScanRel(context.getCluster(), context.getLogicalTraits(),
context.getTable(scan));
}
@Override
public RelDataType deriveRowType() {
return this.rowType;
}
@Override
public RelWriter explainTerms(RelWriter pw) {
return super.explainTerms(pw).item("groupscan", groupScan.getDigest());
}
@Override
public double getRows() {
return this.groupScan.getScanStats().getRecordCount();
}
/// TODO: this method is same as the one for ScanPrel...eventually we should consolidate
/// this and few other methods in a common base class which would be extended
/// by both logical and physical rels.
@Override
public RelOptCost computeSelfCost(RelOptPlanner planner) {
ScanStats stats = groupScan.getScanStats();
int columnCount = getRowType().getFieldCount();
double ioCost = 0;
boolean isStarQuery = Iterables.tryFind(getRowType().getFieldNames(), new Predicate<String>() {
@Override
public boolean apply(String input) {
return Preconditions.checkNotNull(input).equals("*");
}
}).isPresent();
if (isStarQuery) {
columnCount = STAR_COLUMN_COST;
}
// double rowCount = RelMetadataQuery.getRowCount(this);
double rowCount = stats.getRecordCount();
if (rowCount < 1) {
rowCount = 1;
}
if(PrelUtil.getSettings(getCluster()).useDefaultCosting()) {
return planner.getCostFactory().makeCost(rowCount * columnCount, stats.getCpuCost(), stats.getDiskCost());
}
double cpuCost = rowCount * columnCount; // for now, assume cpu cost is proportional to row count.
// Even though scan is reading from disk, in the currently generated plans all plans will
// need to read the same amount of data, so keeping the disk io cost 0 is ok for now.
// In the future we might consider alternative scans that go against projections or
// different compression schemes etc that affect the amount of data read. Such alternatives
// would affect both cpu and io cost.
DrillCostFactory costFactory = (DrillCostFactory)planner.getCostFactory();
return costFactory.makeCost(rowCount, cpuCost, ioCost, 0);
}
public GroupScan getGroupScan() {
return groupScan;
}
}