/**
* 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.physical.impl.limit;
import java.util.List;
import org.apache.drill.exec.exception.SchemaChangeException;
import org.apache.drill.exec.memory.OutOfMemoryException;
import org.apache.drill.exec.ops.FragmentContext;
import org.apache.drill.exec.physical.config.Limit;
import org.apache.drill.exec.record.AbstractSingleRecordBatch;
import org.apache.drill.exec.record.BatchSchema;
import org.apache.drill.exec.record.RecordBatch;
import org.apache.drill.exec.record.TransferPair;
import org.apache.drill.exec.record.VectorWrapper;
import org.apache.drill.exec.record.selection.SelectionVector2;
import com.google.common.collect.Lists;
public class LimitRecordBatch extends AbstractSingleRecordBatch<Limit> {
private SelectionVector2 outgoingSv;
private SelectionVector2 incomingSv;
private int recordsToSkip;
private int recordsLeft;
private boolean noEndLimit;
private boolean skipBatch;
List<TransferPair> transfers = Lists.newArrayList();
public LimitRecordBatch(Limit popConfig, FragmentContext context, RecordBatch incoming) throws OutOfMemoryException {
super(popConfig, context, incoming);
outgoingSv = new SelectionVector2(oContext.getAllocator());
recordsToSkip = popConfig.getFirst();
noEndLimit = popConfig.getLast() == null;
if(!noEndLimit) {
recordsLeft = popConfig.getLast() - recordsToSkip;
}
skipBatch = false;
}
@Override
protected void setupNewSchema() throws SchemaChangeException {
container.clear();
for(VectorWrapper<?> v : incoming){
TransferPair pair = v.getValueVector().getTransferPair();
container.add(pair.getTo());
transfers.add(pair);
}
BatchSchema.SelectionVectorMode svMode = incoming.getSchema().getSelectionVectorMode();
switch(svMode){
case NONE:
break;
case TWO_BYTE:
this.incomingSv = incoming.getSelectionVector2();
break;
default:
throw new UnsupportedOperationException();
}
container.buildSchema(BatchSchema.SelectionVectorMode.TWO_BYTE);
}
@Override
public IterOutcome innerNext() {
if(!noEndLimit && recordsLeft <= 0) {
incoming.kill(true);
IterOutcome upStream = incoming.next();
while (upStream == IterOutcome.OK || upStream == IterOutcome.OK_NEW_SCHEMA) {
// Clear the memory for the incoming batch
for (VectorWrapper<?> wrapper : incoming) {
wrapper.getValueVector().clear();
}
upStream = incoming.next();
}
return IterOutcome.NONE;
}
return super.innerNext();
}
@Override
public SelectionVector2 getSelectionVector2() {
return outgoingSv;
}
@Override
protected void doWork() {
for(TransferPair tp : transfers) {
tp.transfer();
}
skipBatch = false;
int recordCount = incoming.getRecordCount();
if(recordCount <= recordsToSkip) {
recordsToSkip -= recordCount;
skipBatch = true;
} else {
outgoingSv.allocateNew(recordCount);
if(incomingSv != null) {
limitWithSV(recordCount);
} else {
limitWithNoSV(recordCount);
}
}
}
private void limitWithNoSV(int recordCount) {
int offset = Math.max(0, Math.min(recordCount - 1, recordsToSkip));
recordsToSkip -= offset;
int fetch;
if(noEndLimit) {
fetch = recordCount;
} else {
fetch = Math.min(recordCount, offset + recordsLeft);
recordsLeft -= Math.max(0, fetch - offset);
}
int svIndex = 0;
for(char i = (char) offset; i < fetch; i++) {
outgoingSv.setIndex(svIndex, i);
svIndex++;
}
outgoingSv.setRecordCount(svIndex);
}
private void limitWithSV(int recordCount) {
int offset = Math.max(0, Math.min(recordCount - 1, recordsToSkip));
recordsToSkip -= offset;
int fetch;
if(noEndLimit) {
fetch = recordCount;
} else {
fetch = Math.min(recordCount, recordsLeft);
recordsLeft -= Math.max(0, fetch - offset);
}
int svIndex = 0;
for(int i = offset; i < fetch; i++) {
char index = incomingSv.getIndex(i);
outgoingSv.setIndex(svIndex, index);
svIndex++;
}
outgoingSv.setRecordCount(svIndex);
}
@Override
public int getRecordCount() {
return skipBatch ? 0 : outgoingSv.getCount();
}
@Override
public void cleanup(){
outgoingSv.clear();
super.cleanup();
}
}