/**
* 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.store.sys;
import java.io.IOException;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import com.fasterxml.jackson.annotation.JacksonInject;
import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonTypeName;
import com.google.common.collect.Lists;
import org.apache.drill.common.exceptions.ExecutionSetupException;
import org.apache.drill.common.expression.SchemaPath;
import org.apache.drill.exec.physical.EndpointAffinity;
import org.apache.drill.exec.physical.PhysicalOperatorSetupException;
import org.apache.drill.exec.physical.base.AbstractGroupScan;
import org.apache.drill.exec.physical.base.GroupScan;
import org.apache.drill.exec.physical.base.PhysicalOperator;
import org.apache.drill.exec.physical.base.ScanStats;
import org.apache.drill.exec.physical.base.SubScan;
import org.apache.drill.exec.planner.fragment.DistributionAffinity;
import org.apache.drill.exec.proto.CoordinationProtos.DrillbitEndpoint;
import org.apache.drill.exec.proto.UserBitShared.CoreOperatorType;
import org.apache.drill.exec.store.StoragePluginRegistry;
@JsonTypeName("sys")
public class SystemTableScan extends AbstractGroupScan implements SubScan {
// private static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(SystemTableScan.class);
private final SystemTable table;
private final SystemTablePlugin plugin;
@JsonCreator
public SystemTableScan( //
@JsonProperty("table") SystemTable table, //
@JacksonInject StoragePluginRegistry engineRegistry //
) throws IOException, ExecutionSetupException {
super((String)null);
this.table = table;
this.plugin = (SystemTablePlugin) engineRegistry.getPlugin(SystemTablePluginConfig.INSTANCE);
}
public SystemTableScan(SystemTable table, SystemTablePlugin plugin) {
super((String)null);
this.table = table;
this.plugin = plugin;
}
/**
* System tables do not need stats.
* @return a trivial stats table
*/
@Override
public ScanStats getScanStats() {
return ScanStats.TRIVIAL_TABLE;
}
@Override
public PhysicalOperator getNewWithChildren(List<PhysicalOperator> children) throws ExecutionSetupException {
return new SystemTableScan(table, plugin);
}
@Override
public void applyAssignments(List<DrillbitEndpoint> endpoints) throws PhysicalOperatorSetupException {
}
@Override
public SubScan getSpecificScan(int minorFragmentId) throws ExecutionSetupException {
return this;
}
// If distributed, the scan needs to happen on every node.
@Override
public int getMaxParallelizationWidth() {
return table.isDistributed() ? plugin.getContext().getBits().size() : 1;
}
// If distributed, the scan needs to happen on every node.
@Override
public int getMinParallelizationWidth() {
return table.isDistributed() ? plugin.getContext().getBits().size() : 1;
}
@Override
public long getInitialAllocation() {
return initialAllocation;
}
@Override
public long getMaxAllocation() {
return maxAllocation;
}
@Override
public String getDigest() {
return "SystemTableScan [table=" + table.name() +
", distributed=" + table.isDistributed() + "]";
}
@Override
public int getOperatorType() {
return CoreOperatorType.SYSTEM_TABLE_SCAN_VALUE;
}
/**
* If distributed, the scan needs to happen on every node. Since width is enforced, the number of fragments equals
* number of Drillbits. And here we set, each endpoint as mandatory assignment required to ensure every
* Drillbit executes a fragment.
* @return the Drillbit endpoint affinities
*/
@Override
public List<EndpointAffinity> getOperatorAffinity() {
if (table.isDistributed()) {
final List<EndpointAffinity> affinities = Lists.newArrayList();
final Collection<DrillbitEndpoint> bits = plugin.getContext().getBits();
final double affinityPerNode = 1d / bits.size();
for (final DrillbitEndpoint endpoint : bits) {
affinities.add(new EndpointAffinity(endpoint, affinityPerNode, true, /* maxWidth = */ 1));
}
return affinities;
} else {
return Collections.emptyList();
}
}
@Override
public DistributionAffinity getDistributionAffinity() {
return table.isDistributed() ? DistributionAffinity.HARD : DistributionAffinity.SOFT;
}
@Override
public GroupScan clone(List<SchemaPath> columns) {
return this;
}
public SystemTable getTable() {
return table;
}
@JsonIgnore
public SystemTablePlugin getPlugin() {
return plugin;
}
}