| /* |
| * 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.iotdb.db.queryengine.execution.operator.process; |
| |
| import org.apache.iotdb.db.queryengine.execution.operator.AbstractOperator; |
| import org.apache.iotdb.db.queryengine.execution.operator.Operator; |
| import org.apache.iotdb.db.queryengine.execution.operator.OperatorContext; |
| |
| import com.google.common.util.concurrent.ListenableFuture; |
| import org.apache.tsfile.read.common.block.TsBlock; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| import java.util.concurrent.TimeUnit; |
| |
| import static com.google.common.util.concurrent.Futures.successfulAsList; |
| |
| /** ConsumeAllOperator will consume all children's result every time. */ |
| public abstract class AbstractConsumeAllOperator extends AbstractOperator |
| implements ProcessOperator { |
| protected final List<Operator> children; |
| protected final int inputOperatorsCount; |
| /** TsBlock from child operator. Only one cache now. */ |
| protected TsBlock[] inputTsBlocks; |
| |
| protected final boolean[] canCallNext; |
| protected int readyChildIndex; |
| |
| /** Index of the child that is currently fetching input */ |
| protected int currentChildIndex = 0; |
| |
| /** Indicate whether we found an empty child input in one loop */ |
| protected boolean hasEmptyChildInput = false; |
| |
| protected AbstractConsumeAllOperator(OperatorContext operatorContext, List<Operator> children) { |
| this.operatorContext = operatorContext; |
| this.children = children; |
| this.inputOperatorsCount = children.size(); |
| this.inputTsBlocks = new TsBlock[inputOperatorsCount]; |
| this.canCallNext = new boolean[inputOperatorsCount]; |
| for (int i = 0; i < inputOperatorsCount; i++) { |
| canCallNext[i] = false; |
| } |
| } |
| |
| @Override |
| public ListenableFuture<?> isBlocked() { |
| boolean hasReadyChild = false; |
| readyChildIndex = 0; |
| List<ListenableFuture<?>> listenableFutures = new ArrayList<>(); |
| for (int i = 0; i < inputOperatorsCount; i++) { |
| if (!isEmpty(i) || children.get(i) == null) { |
| continue; |
| } |
| ListenableFuture<?> blocked = children.get(i).isBlocked(); |
| if (blocked.isDone()) { |
| hasReadyChild = true; |
| canCallNext[i] = true; |
| readyChildIndex = i; |
| } else { |
| listenableFutures.add(blocked); |
| } |
| } |
| return (hasReadyChild || listenableFutures.isEmpty()) |
| ? NOT_BLOCKED |
| : successfulAsList(listenableFutures); |
| } |
| |
| /** |
| * Try to cache one result of each child. |
| * |
| * @return true if results of all children are ready. Return false if some children is blocked or |
| * return null. |
| * @throws Exception errors happened while getting tsblock from children |
| */ |
| protected boolean prepareInput() throws Exception { |
| // start stopwatch |
| long maxRuntime = operatorContext.getMaxRunTime().roundTo(TimeUnit.NANOSECONDS); |
| long start = System.nanoTime(); |
| |
| while (System.nanoTime() - start < maxRuntime && currentChildIndex < inputOperatorsCount) { |
| if (canSkipCurrentChild(currentChildIndex)) { |
| currentChildIndex++; |
| continue; |
| } |
| if (canCallNext[currentChildIndex]) { |
| if (children.get(currentChildIndex).hasNextWithTimer()) { |
| inputTsBlocks[currentChildIndex] = getNextTsBlock(currentChildIndex); |
| canCallNext[currentChildIndex] = false; |
| // child operator has next but return an empty TsBlock which means that it may not |
| // finish calculation in given time slice. |
| // In such case, TimeJoinOperator can't go on calculating, so we just return null. |
| // We can also use the while loop here to continuously call the hasNext() and next() |
| // methods of the child operator until its hasNext() returns false or the next() gets |
| // the data that is not empty, but this will cause the execution time of the while loop |
| // to be uncontrollable and may exceed all allocated time slice |
| if (isEmpty(currentChildIndex)) { |
| hasEmptyChildInput = true; |
| } else { |
| processCurrentInputTsBlock(currentChildIndex); |
| } |
| } else { |
| handleFinishedChild(currentChildIndex); |
| } |
| } else { |
| hasEmptyChildInput = true; |
| } |
| currentChildIndex++; |
| } |
| |
| if (currentChildIndex == inputOperatorsCount) { |
| // start a new loop |
| currentChildIndex = 0; |
| if (!hasEmptyChildInput) { |
| // all children are ready now |
| return true; |
| } else { |
| // In a new loop, previously empty child input could be non-empty now, and we can skip the |
| // children that have generated input |
| hasEmptyChildInput = false; |
| } |
| } |
| return false; |
| } |
| |
| /** If the tsBlock is null or has no more data in the tsBlock, return true; else return false. */ |
| protected boolean isEmpty(int index) { |
| return inputTsBlocks[index] == null || inputTsBlocks[index].isEmpty(); |
| } |
| |
| // region helper function used in prepareInput, the subclass can have its own implementation |
| |
| /** |
| * @param currentChildIndex the index of the child |
| * @return true if we can skip the currentChild in prepareInput |
| */ |
| protected boolean canSkipCurrentChild(int currentChildIndex) { |
| return !isEmpty(currentChildIndex) || children.get(currentChildIndex) == null; |
| } |
| |
| /** @param currentInputIndex index of the input TsBlock */ |
| protected void processCurrentInputTsBlock(int currentInputIndex) { |
| // do nothing here, the subclass have its own implementation |
| } |
| |
| /** |
| * @param currentChildIndex the index of the child |
| * @throws Exception Potential Exception thrown by Operator.close() |
| */ |
| protected void handleFinishedChild(int currentChildIndex) throws Exception { |
| children.get(currentChildIndex).close(); |
| children.set(currentChildIndex, null); |
| } |
| |
| // endregion |
| |
| @Override |
| public void close() throws Exception { |
| for (Operator child : children) { |
| if (child != null) { |
| child.close(); |
| } |
| } |
| // friendly for gc |
| inputTsBlocks = null; |
| } |
| |
| protected TsBlock getNextTsBlock(int childIndex) throws Exception { |
| return children.get(childIndex).nextWithTimer(); |
| } |
| } |