io.prestosql.operator.NoChannelGroupByHash Maven / Gradle / Ivy
/*
* Licensed 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 io.prestosql.operator;
import com.google.common.collect.ImmutableList;
import io.prestosql.spi.Page;
import io.prestosql.spi.PageBuilder;
import io.prestosql.spi.block.RunLengthEncodedBlock;
import io.prestosql.spi.type.Type;
import org.openjdk.jol.info.ClassLayout;
import java.util.List;
import static io.prestosql.spi.type.BigintType.BIGINT;
public class NoChannelGroupByHash
implements GroupByHash
{
private static final int INSTANCE_SIZE = ClassLayout.parseClass(NoChannelGroupByHash.class).instanceSize();
private int groupCount;
@Override
public long getEstimatedSize()
{
return INSTANCE_SIZE;
}
@Override
public long getHashCollisions()
{
return 0;
}
@Override
public double getExpectedHashCollisions()
{
return 0;
}
@Override
public List getTypes()
{
return ImmutableList.of();
}
@Override
public int getGroupCount()
{
return groupCount;
}
@Override
public void appendValuesTo(int groupId, PageBuilder pageBuilder, int outputChannelOffset)
{
throw new UnsupportedOperationException("NoChannelGroupByHash does not support appendValuesTo");
}
@Override
public Work> addPage(Page page)
{
updateGroupCount(page);
// create a dump work whose result is never used.
return new CompletedWork<>(0);
}
@Override
public Work getGroupIds(Page page)
{
updateGroupCount(page);
return new CompletedWork<>(new GroupByIdBlock(page.getPositionCount() > 0 ? 1 : 0, RunLengthEncodedBlock.create(BIGINT, 0L, page.getPositionCount())));
}
@Override
public boolean contains(int position, Page page, int[] hashChannels)
{
throw new UnsupportedOperationException("NoChannelGroupByHash does not support getHashCollisions");
}
@Override
public long getRawHash(int groupyId)
{
throw new UnsupportedOperationException("NoChannelGroupByHash does not support getHashCollisions");
}
@Override
public int getCapacity()
{
return 2;
}
private void updateGroupCount(Page page)
{
if (page.getPositionCount() > 0 && groupCount == 0) {
groupCount = 1;
}
}
}
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