/**
* 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.mongo;
import java.io.IOException;
import org.apache.drill.common.exceptions.DrillRuntimeException;
import org.apache.drill.common.expression.LogicalExpression;
import org.apache.drill.exec.planner.logical.DrillOptiq;
import org.apache.drill.exec.planner.logical.DrillParseContext;
import org.apache.drill.exec.planner.logical.RelOptHelper;
import org.apache.drill.exec.planner.physical.FilterPrel;
import org.apache.drill.exec.planner.physical.ScanPrel;
import org.apache.drill.exec.store.StoragePluginOptimizerRule;
import org.eigenbase.rel.RelNode;
import org.eigenbase.relopt.RelOptRuleCall;
import org.eigenbase.rex.RexNode;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.google.common.collect.ImmutableList;
public class MongoPushDownFilterForScan extends StoragePluginOptimizerRule {
private static final Logger logger = LoggerFactory
.getLogger(MongoPushDownFilterForScan.class);
public static final StoragePluginOptimizerRule INSTANCE = new MongoPushDownFilterForScan();
private MongoPushDownFilterForScan() {
super(
RelOptHelper.some(FilterPrel.class, RelOptHelper.any(ScanPrel.class)),
"MongoPushDownFilterForScan");
}
@Override
public void onMatch(RelOptRuleCall call) {
final ScanPrel scan = (ScanPrel) call.rel(1);
final FilterPrel filter = (FilterPrel) call.rel(0);
final RexNode condition = filter.getCondition();
MongoGroupScan groupScan = (MongoGroupScan) scan.getGroupScan();
if (groupScan.isFilterPushedDown()) {
return;
}
LogicalExpression conditionExp = DrillOptiq.toDrill(
new DrillParseContext(), scan, condition);
MongoFilterBuilder mongoFilterBuilder = new MongoFilterBuilder(groupScan,
conditionExp);
MongoScanSpec newScanSpec = mongoFilterBuilder.parseTree();
if (newScanSpec == null) {
return; // no filter pushdown so nothing to apply.
}
MongoGroupScan newGroupsScan = null;
try {
newGroupsScan = new MongoGroupScan(groupScan.getStoragePlugin(),
newScanSpec, groupScan.getColumns());
} catch (IOException e) {
logger.error(e.getMessage(), e);
throw new DrillRuntimeException(e.getMessage(), e);
}
newGroupsScan.setFilterPushedDown(true);
final ScanPrel newScanPrel = ScanPrel.create(scan, filter.getTraitSet(),
newGroupsScan, scan.getRowType());
if (mongoFilterBuilder.isAllExpressionsConverted()) {
/*
* Since we could convert the entire filter condition expression into an
* Mongo filter, we can eliminate the filter operator altogether.
*/
call.transformTo(newScanPrel);
} else {
call.transformTo(filter.copy(filter.getTraitSet(),
ImmutableList.of((RelNode) newScanPrel)));
}
}
@Override
public boolean matches(RelOptRuleCall call) {
final ScanPrel scan = (ScanPrel) call.rel(1);
if (scan.getGroupScan() instanceof MongoGroupScan) {
return super.matches(call);
}
return false;
}
}