clintropolis commented on a change in pull request #5712: HllSketch module URL: https://github.com/apache/incubator-druid/pull/5712#discussion_r217831371
########## File path: extensions-core/datasketches/src/main/java/io/druid/query/aggregation/datasketches/hll/HllSketchMergeBufferAggregator.java ########## @@ -0,0 +1,132 @@ +/* + * Licensed to Metamarkets Group Inc. (Metamarkets) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. Metamarkets 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 io.druid.query.aggregation.datasketches.hll; + +import java.nio.ByteBuffer; +import java.util.concurrent.locks.Lock; +import java.util.concurrent.locks.ReadWriteLock; + +import com.google.common.util.concurrent.Striped; +import com.yahoo.memory.WritableMemory; +import com.yahoo.sketches.hll.HllSketch; +import com.yahoo.sketches.hll.TgtHllType; +import com.yahoo.sketches.hll.Union; + +import io.druid.query.aggregation.BufferAggregator; +import io.druid.segment.ColumnValueSelector; + +/** + * This aggregator merges existing sketches. + * The input column must contain {@link HllSketch} + * @author Alexander Saydakov + */ +public class HllSketchMergeBufferAggregator implements BufferAggregator +{ + + private static final int NUM_STRIPES = 64; // for locking per buffer position (power of 2 to make index computation faster) + + private final ColumnValueSelector<HllSketch> selector; + private final int lgK; + private final TgtHllType tgtHllType; + private final int size; + private final Striped<ReadWriteLock> stripedLock = Striped.readWriteLock(NUM_STRIPES); + + public HllSketchMergeBufferAggregator( + final ColumnValueSelector<HllSketch> selector, + final int lgK, + final TgtHllType tgtHllType, + final int size + ) + { + this.selector = selector; + this.lgK = lgK; + this.tgtHllType = tgtHllType; + this.size = size; + } + + @Override + public void init(final ByteBuffer buf, final int position) + { + final WritableMemory mem = WritableMemory.wrap(buf).writableRegion(position, size); + new Union(lgK, mem); Review comment: Oops, yes my bad ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
